Fertility Symbol<\/h1>\r\n<\/div>\r\nThe geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.\r\n\r\nFemale Reproductive Organs<\/h1>\r\n<\/div>\r\nThe female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary]. The internal female reproductive organs include the vagina, [pb_glossary id=\"5102\"]uterus[\/pb_glossary], [pb_glossary id=\"5101\"]oviducts<\/span>[\/pb_glossary]<\/span>, and [pb_glossary id=\"3487\"]ovaries[\/pb_glossary]. The external organs \u2014 collectively called the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] \u2014 include the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary] and [pb_glossary id=\"5154\"]labia[\/pb_glossary].<\/span>\r\n\r\nThe\u00a0[pb_glossary id=\"5143\"]vagina[\/pb_glossary]<\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the [pb_glossary id=\"5235\"]cervix[\/pb_glossary]. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where [pb_glossary id=\"2506\"]sperm[\/pb_glossary] are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary].\r\nStructure of the Vagina<\/h2>\r\nMuscles and ligaments support the vagina within the [pb_glossary id=\"2992\"]pelvic cavity[\/pb_glossary]. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with [pb_glossary id=\"3538\"]mucous membranes<\/span>[\/pb_glossary]<\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span>\r\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\r\nA healthy [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is home to many [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary]\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary] that help prevent pathogens (such as yeast) from colonizing the vagina. The [pb_glossary id=\"4330\"]pH[\/pb_glossary] in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.\r\n\r\nUterus<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5102\"]uterus[\/pb_glossary]<\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the [pb_glossary id=\"4731\"]bladder[\/pb_glossary] in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.\r\n\r\n[caption id=\"attachment_5240\" align=\"alignright\" width=\"368\"]![\"18.6.2](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/1000px-Gray1167.svg_-2.png\")
Figure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em>[\/caption]\r\nParts of the Uterus<\/h2>\r\nAs shown in Figure 18.6.2, the lower end of the uterus forms the [pb_glossary id=\"5235\"]cervix[\/pb_glossary],<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep [pb_glossary id=\"5775\"]microorganisms<\/span>[\/pb_glossary]<\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of [pb_glossary id=\"5239\"]ovulation[\/pb_glossary]. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two [pb_glossary id=\"5101\"]oviduct<\/span>s<\/span>[\/pb_glossary]<\/span>.<\/span>\r\nTissues of the Uterus<\/h2>\r\nAs indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.\r\n\r\n \t- The\u00a0[pb_glossary id=\"5241\"]endometrium[\/pb_glossary]<\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\r\n \t
- The [pb_glossary id=\"5242\"]placenta[\/pb_glossary]<\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5243\"]myometrium[\/pb_glossary]<\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5244\"]perimetrium[\/pb_glossary]<\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_5245\" align=\"aligncenter\" width=\"380\"]
![\"18.6.3](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Uterine_anatomy.-e1593113913396-2.jpg\")
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\n\r\n\r\nOviducts<\/span>\r\n\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5101\"]oviduct<\/strong>s<\/strong>[\/pb_glossary]<\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] and the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the [pb_glossary id=\"5102\"]uterus[\/pb_glossary] on either side of the body. They open into the uterus.<\/span>\r\n\r\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with [pb_glossary id=\"1597\"]cilia[\/pb_glossary], which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the [pb_glossary id=\"5489\"]plasma membrane[\/pb_glossary] of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the [pb_glossary id=\"2982\"]smooth muscle[\/pb_glossary] allow [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] to help move eggs through the tubes.\r\n\r\nOvaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"]![\"18.6.4](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Sites_of_tubo_ovarian_abscess-e1593120204450-2.png\")
Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"]![\"18.6.4](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Ovarian_follicle-2.png\")
Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"]![\"18.6.5](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/HumanVulva-NewText-PhiloViv-2.jpg\")
Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"]![\"18.6.6](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Vulva-2.jpg\")
Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"]![\"18.6.7](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Breast-Diagram-3.gif\")
Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\n![\"18.6.1\"](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2019\/06\/1024px-Cattien_stone_yoni-2.png\")
Figure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Female Reproductive Organs<\/h1>\r\n<\/div>\r\nThe female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary]. The internal female reproductive organs include the vagina, [pb_glossary id=\"5102\"]uterus[\/pb_glossary], [pb_glossary id=\"5101\"]oviducts<\/span>[\/pb_glossary]<\/span>, and [pb_glossary id=\"3487\"]ovaries[\/pb_glossary]. The external organs \u2014 collectively called the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] \u2014 include the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary] and [pb_glossary id=\"5154\"]labia[\/pb_glossary].<\/span>\r\n\r\nThe\u00a0[pb_glossary id=\"5143\"]vagina[\/pb_glossary]<\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the [pb_glossary id=\"5235\"]cervix[\/pb_glossary]. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where [pb_glossary id=\"2506\"]sperm[\/pb_glossary] are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary].\r\nStructure of the Vagina<\/h2>\r\nMuscles and ligaments support the vagina within the [pb_glossary id=\"2992\"]pelvic cavity[\/pb_glossary]. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with [pb_glossary id=\"3538\"]mucous membranes<\/span>[\/pb_glossary]<\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span>\r\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\r\nA healthy [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is home to many [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary]\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary] that help prevent pathogens (such as yeast) from colonizing the vagina. The [pb_glossary id=\"4330\"]pH[\/pb_glossary] in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.\r\n\r\nUterus<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5102\"]uterus[\/pb_glossary]<\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the [pb_glossary id=\"4731\"]bladder[\/pb_glossary] in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.\r\n\r\n[caption id=\"attachment_5240\" align=\"alignright\" width=\"368\"] Figure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em>[\/caption]\r\nParts of the Uterus<\/h2>\r\nAs shown in Figure 18.6.2, the lower end of the uterus forms the [pb_glossary id=\"5235\"]cervix[\/pb_glossary],<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep [pb_glossary id=\"5775\"]microorganisms<\/span>[\/pb_glossary]<\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of [pb_glossary id=\"5239\"]ovulation[\/pb_glossary]. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two [pb_glossary id=\"5101\"]oviduct<\/span>s<\/span>[\/pb_glossary]<\/span>.<\/span>\r\nTissues of the Uterus<\/h2>\r\nAs indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.\r\n\r\n \t- The\u00a0[pb_glossary id=\"5241\"]endometrium[\/pb_glossary]<\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\r\n \t
- The [pb_glossary id=\"5242\"]placenta[\/pb_glossary]<\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5243\"]myometrium[\/pb_glossary]<\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5244\"]perimetrium[\/pb_glossary]<\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_5245\" align=\"aligncenter\" width=\"380\"] Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\n\r\n\r\nOviducts<\/span>\r\n\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5101\"]oviduct<\/strong>s<\/strong>[\/pb_glossary]<\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] and the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the [pb_glossary id=\"5102\"]uterus[\/pb_glossary] on either side of the body. They open into the uterus.<\/span>\r\n\r\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with [pb_glossary id=\"1597\"]cilia[\/pb_glossary], which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the [pb_glossary id=\"5489\"]plasma membrane[\/pb_glossary] of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the [pb_glossary id=\"2982\"]smooth muscle[\/pb_glossary] allow [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] to help move eggs through the tubes.\r\n\r\n
Ovaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"] Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"] Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Bacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\r\nA healthy [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is home to many [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary]\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary] that help prevent pathogens (such as yeast) from colonizing the vagina. The [pb_glossary id=\"4330\"]pH[\/pb_glossary] in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.\r\n\r\nUterus<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5102\"]uterus[\/pb_glossary]<\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the [pb_glossary id=\"4731\"]bladder[\/pb_glossary] in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.\r\n\r\n[caption id=\"attachment_5240\" align=\"alignright\" width=\"368\"] Figure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em>[\/caption]\r\nParts of the Uterus<\/h2>\r\nAs shown in Figure 18.6.2, the lower end of the uterus forms the [pb_glossary id=\"5235\"]cervix[\/pb_glossary],<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep [pb_glossary id=\"5775\"]microorganisms<\/span>[\/pb_glossary]<\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of [pb_glossary id=\"5239\"]ovulation[\/pb_glossary]. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two [pb_glossary id=\"5101\"]oviduct<\/span>s<\/span>[\/pb_glossary]<\/span>.<\/span>\r\nTissues of the Uterus<\/h2>\r\nAs indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.\r\n\r\n \t- The\u00a0[pb_glossary id=\"5241\"]endometrium[\/pb_glossary]<\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\r\n \t
- The [pb_glossary id=\"5242\"]placenta[\/pb_glossary]<\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5243\"]myometrium[\/pb_glossary]<\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5244\"]perimetrium[\/pb_glossary]<\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_5245\" align=\"aligncenter\" width=\"380\"] Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\n\r\n\r\nOviducts<\/span>\r\n\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5101\"]oviduct<\/strong>s<\/strong>[\/pb_glossary]<\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] and the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the [pb_glossary id=\"5102\"]uterus[\/pb_glossary] on either side of the body. They open into the uterus.<\/span>\r\n\r\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with [pb_glossary id=\"1597\"]cilia[\/pb_glossary], which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the [pb_glossary id=\"5489\"]plasma membrane[\/pb_glossary] of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the [pb_glossary id=\"2982\"]smooth muscle[\/pb_glossary] allow [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] to help move eggs through the tubes.\r\n\r\n
Ovaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"] Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"] Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Uterus<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5102\"]uterus[\/pb_glossary]<\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the [pb_glossary id=\"4731\"]bladder[\/pb_glossary] in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.\r\n\r\n[caption id=\"attachment_5240\" align=\"alignright\" width=\"368\"] Figure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em>[\/caption]\r\nParts of the Uterus<\/h2>\r\nAs shown in Figure 18.6.2, the lower end of the uterus forms the [pb_glossary id=\"5235\"]cervix[\/pb_glossary],<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep [pb_glossary id=\"5775\"]microorganisms<\/span>[\/pb_glossary]<\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of [pb_glossary id=\"5239\"]ovulation[\/pb_glossary]. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two [pb_glossary id=\"5101\"]oviduct<\/span>s<\/span>[\/pb_glossary]<\/span>.<\/span>\r\nTissues of the Uterus<\/h2>\r\nAs indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.\r\n\r\n \t- The\u00a0[pb_glossary id=\"5241\"]endometrium[\/pb_glossary]<\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\r\n \t
- The [pb_glossary id=\"5242\"]placenta[\/pb_glossary]<\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5243\"]myometrium[\/pb_glossary]<\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5244\"]perimetrium[\/pb_glossary]<\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_5245\" align=\"aligncenter\" width=\"380\"] Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\n\r\n\r\nOviducts<\/span>\r\n\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5101\"]oviduct<\/strong>s<\/strong>[\/pb_glossary]<\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] and the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the [pb_glossary id=\"5102\"]uterus[\/pb_glossary] on either side of the body. They open into the uterus.<\/span>\r\n\r\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with [pb_glossary id=\"1597\"]cilia[\/pb_glossary], which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the [pb_glossary id=\"5489\"]plasma membrane[\/pb_glossary] of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the [pb_glossary id=\"2982\"]smooth muscle[\/pb_glossary] allow [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] to help move eggs through the tubes.\r\n\r\n
Ovaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"] Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"] Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Tissues of the Uterus<\/h2>\r\nAs indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.\r\n\r\n \t- The\u00a0[pb_glossary id=\"5241\"]endometrium[\/pb_glossary]<\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\r\n \t
- The [pb_glossary id=\"5242\"]placenta[\/pb_glossary]<\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5243\"]myometrium[\/pb_glossary]<\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\r\n \t
- The\u00a0[pb_glossary id=\"5244\"]perimetrium[\/pb_glossary]<\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_5245\" align=\"aligncenter\" width=\"380\"] Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\n\r\n\r\nOviducts<\/span>\r\n\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5101\"]oviduct<\/strong>s<\/strong>[\/pb_glossary]<\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] and the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the [pb_glossary id=\"5102\"]uterus[\/pb_glossary] on either side of the body. They open into the uterus.<\/span>\r\n\r\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with [pb_glossary id=\"1597\"]cilia[\/pb_glossary], which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the [pb_glossary id=\"5489\"]plasma membrane[\/pb_glossary] of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the [pb_glossary id=\"2982\"]smooth muscle[\/pb_glossary] allow [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] to help move eggs through the tubes.\r\n\r\n
Ovaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"] Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"] Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em>[\/caption]\r\n\r\nOvaries<\/h1>\r\n<\/div>\r\nLike the [pb_glossary id=\"3486\"]testes[\/pb_glossary] in males, the\u00a0[pb_glossary id=\"3487\"]ovaries[\/pb_glossary]<\/strong>\u00a0in females are [pb_glossary id=\"3408\"]gonads<\/span>[\/pb_glossary]<\/span>\u00a0that produce [pb_glossary id=\"6023\"]gamete<\/span>s<\/span>[\/pb_glossary]<\/span> and secrete sex [pb_glossary id=\"5661\"]hormones[\/pb_glossary]. The gametes produced by the ovaries are called [pb_glossary id=\"5099\"]ova[\/pb_glossary], or oocytes. The main sex hormone secreted by the ovaries is [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span>\r\n\r\n[caption id=\"attachment_5251\" align=\"aligncenter\" width=\"689\"] Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em>[\/caption]\r\nOvarian Follicles<\/h2>\r\nThe ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0[pb_glossary id=\"5835\"]blood[\/pb_glossary]\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0[pb_glossary id=\"5253\"]ovarian follicle<\/strong>s<\/strong>[\/pb_glossary].<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called [pb_glossary id=\"5239\"]ovulation[\/pb_glossary].<\/span>\r\n\r\n[caption id=\"attachment_5254\" align=\"aligncenter\" width=\"800\"] Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em>[\/caption]\r\nOva in the Ovaries<\/h2>\r\nWhereas the male [pb_glossary id=\"3486\"]testes[\/pb_glossary] produce sperm continuously after\u00a0[pb_glossary id=\"5155\"]puberty[\/pb_glossary], the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] contain at least a million eggs, each of which is contained within a [pb_glossary id=\"5253\"]follicle[\/pb_glossary]. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until [pb_glossary id=\"5255\"]menopause[\/pb_glossary] occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and [pb_glossary id=\"5239\"]ovulation[\/pb_glossary] no longer occurs.\r\n\r\nVulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Vulva<\/h1>\r\n<\/div>\r\nThe\u00a0[pb_glossary id=\"5152\"]vulva[\/pb_glossary]<\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.\r\nLabia<\/h2>\r\nThe\u00a0[pb_glossary id=\"5154\"]labia[\/pb_glossary]<\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.\r\n\r\n[caption id=\"attachment_5256\" align=\"aligncenter\" width=\"361\"] Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em>[\/caption]\r\nClitoris<\/h2>\r\nThe\u00a0[pb_glossary id=\"5153\"]clitoris[\/pb_glossary],<\/strong>\u00a0is located at the front of the [pb_glossary id=\"5152\"]vulva[\/pb_glossary] where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span>\r\n\r\n[caption id=\"attachment_5257\" align=\"aligncenter\" width=\"729\"] Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em>[\/caption]\r\nOther Vulvar Structures<\/h2>\r\nThe area between the two labia minora is called the vestibule of the vulva. Both the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary] have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.\r\n\r\nBreasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
Breasts<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_5258\" align=\"alignright\" width=\"350\"] Figure 18.6.8 The breasts are not really reproductive organs, but they play a reproductive role as mammary glands that can produce milk to feed an infant.<\/em>[\/caption]\r\n\r\nThe breasts are not directly involved in\u00a0reproduction, but because they contain\u00a0[pb_glossary id=\"3432\"]mammary gland<\/strong>s<\/strong>[\/pb_glossary],<\/strong> they can provide nourishment to an infant after birth. The breasts overlay major muscles in the chest from which they project outward in a conical shape. The two main types of tissues in the breast are adipose (fat) tissue and glandular tissue that produces milk. As shown in Figure 18.6.8, each mature breast contains many lobules, where milk is produced and stored during pregnancy. During breastfeeding (or lactation), the milk drains into ducts and sacs, which in turn converge at the nipple. Milk exits the breast through the nipple in response to the suckling action of an infant and is regulated by a [pb_glossary id=\"2962\"]positive feedback loop[\/pb_glossary]. The nipple is surrounded by a more darkly pigmented area called the areola. The areola contains glands that secrete an oily fluid, which lubricates and protects the nipple during breastfeeding.<\/span>\r\n\r\n\r\n18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
18.6 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\nAttributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\nJanux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":" <\/p>\nFigure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n\nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\nThe\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\nStructure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\nBacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\nFigure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\nParts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\nTissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
\n- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n\nOviducts<\/span><\/p>\n<\/div>\nThe\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\nThe oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\nFigure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\nOvarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\nFigure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\nOva in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\nLabia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\nFigure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\nClitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\nFigure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\nOther Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n\nBreasts<\/h1>\n<\/div>\n
- \r\n \t
- The\u00a0female reproductive system\u00a0is made up of internal and external organs that function to produce [pb_glossary id=\"2484\"]haploid[\/pb_glossary] female [pb_glossary id=\"6023\"]gametes[\/pb_glossary] called ova, secrete female sex hormones (such as [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]), and carry and give birth to a [pb_glossary id=\"5086\"]fetus[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5143\"]vagina[\/pb_glossary] is an elastic, muscular canal that can accommodate the [pb_glossary id=\"5091\"]penis[\/pb_glossary]. It is also where sperm are usually ejaculated during [pb_glossary id=\"5149\"]sexual intercourse[\/pb_glossary]. The vagina is the birth canal, and it channels the flow of menstrual blood from the [pb_glossary id=\"5102\"]uterus[\/pb_glossary]. A healthy vagina has a balance of [pb_glossary id=\"5819\"]symbiotic[\/pb_glossary] [pb_glossary id=\"2588\"]bacteria[\/pb_glossary] and an [pb_glossary id=\"5691\"]acidic[\/pb_glossary] [pb_glossary id=\"4330\"]pH[\/pb_glossary].<\/li>\r\n \t
- The [pb_glossary id=\"5102\"]uterus[\/pb_glossary] is a muscular organ above the [pb_glossary id=\"5143\"]vagina[\/pb_glossary] where a [pb_glossary id=\"5086\"]fetus[\/pb_glossary] develops. Its muscular walls contract to push out the fetus during childbirth. The [pb_glossary id=\"5235\"]cervix[\/pb_glossary] is the neck of the uterus that extends down into the vagina. It contains a canal connecting the vagina and uterus for sperm, or for an infant to pass through. The innermost layer of the uterus \u2014 the [pb_glossary id=\"5241\"]endometrium[\/pb_glossary] \u2014 thickens each month in preparation for an [pb_glossary id=\"5262\"]embryo[\/pb_glossary], but is shed in the following menstrual period if\u00a0fertilization does not occur.<\/li>\r\n \t
- The [pb_glossary id=\"5101\"]oviducts[\/pb_glossary]\u00a0extend from the uterus to the ovaries. Waving [pb_glossary id=\"5247\"]fimbriae[\/pb_glossary] at the ovary ends of the oviducts guide ovulated eggs into the tubes where [pb_glossary id=\"6009\"]fertilization[\/pb_glossary] may occur as the ova travel to the uterus. [pb_glossary id=\"1597\"]Cilia[\/pb_glossary] and [pb_glossary id=\"2890\"]peristalsis[\/pb_glossary] help ova move through the tubes. Tubular fluid helps nourish sperm as they swim up the tubes toward ova.<\/li>\r\n \t
- The [pb_glossary id=\"3487\"]ovaries[\/pb_glossary] are [pb_glossary id=\"3408\"]gonads[\/pb_glossary] that produce ova and secrete sex hormones, including [pb_glossary id=\"5995\"]estrogen[\/pb_glossary]. Nests of cells called [pb_glossary id=\"5253\"]follicles[\/pb_glossary] in the ovarian cortex are the functional units of ovaries. Each follicle surrounds an immature ovum. At birth, a baby girl\u2019s ovaries contain at least a million ova, and they will not produce any more during her lifetime. During a woman\u2019s reproductive years, one ova typically matures and is ovulated each month.<\/li>\r\n \t
- The [pb_glossary id=\"5152\"]vulva[\/pb_glossary] is a general term for external female reproductive organs. The vulva includes the [pb_glossary id=\"5153\"]clitoris[\/pb_glossary], two pairs of [pb_glossary id=\"5154\"]labia[\/pb_glossary], and openings for the [pb_glossary id=\"4732\"]urethra[\/pb_glossary] and [pb_glossary id=\"5143\"]vagina[\/pb_glossary]. Secretions from mucosal glands near the vaginal opening lubricate the vulva.<\/li>\r\n \t
- The breasts are not technically reproductive organs, but their [pb_glossary id=\"3432\"]mammary glands[\/pb_glossary] produce milk to feed an infant after birth. Milk drains through ducts and sacs, and out through the nipple when a\u00a0 baby sucks during breastfeeding.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n 18.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n
\r\n- \r\n \t
- [h5p id=\"648\"]<\/li>\r\n \t
- State the general functions of the female reproductive system.<\/li>\r\n \t
- Describe the vagina and its reproductive functions.<\/li>\r\n \t
- Outline the structure and basic functions of the uterus.<\/li>\r\n \t
- What is the endometrium? How does it change during the monthly cycle?<\/li>\r\n \t
- Why are breasts included in discussions of reproduction, if they are not organs of the female reproductive system?<\/li>\r\n \t
- What is the function of the folds in the mucous membrane lining of the vagina?<\/li>\r\n \t
- What are two ways in which the female reproductive system protects itself from pathogens?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n 18.6 Explore More<\/span><\/h1>\r\n<\/header>\r\n
\r\n\r\nhttps:\/\/youtu.be\/SkB4gG8ke7Q\r\nThe uncomplicated truth about women's sexuality | Sarah Barmak, TED, 2019.<\/p>\r\nhttps:\/\/youtu.be\/9rs2gNchQig\r\n
Human Physiology - Functional Anatomy of the Female Reproductive System, Janux, 2015.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
\r\n Attributes<\/h2>\r\nFigure 18.6.1<\/strong>\r\n\r\n1024px-Cattien_stone_yoni<\/a> by Binh Giang<\/a> on Wikimedia Commons is in the \u00a0public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:public_domain).\r\n\r\nFigure 18.6.2<\/strong>\r\n\r\n1000px-Gray1167.svg<\/a> by Henry Vandyke Carter<\/a>\u00a0(1831-1897) on Wikimedia Commons is in the \u00a0public domain<\/a>\u00a0(https:\/\/en.wikipedia.org\/wiki\/public_domain). (Bartleby.com<\/a>:\u00a0Gray\u2019s Anatomy<\/a>, Plate 1167<\/a>).\r\n\r\nFigure 18.6.3<\/strong>\r\n\r\nUterine_anatomy.<\/a> from Uterine Stem cells<\/a> by The Stem Cell Research Community, StemBook<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.4<\/strong>\r\n\r\nSites_of_tubo_ovarian_abscess<\/a> by Bfpage<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\nFigure 18.6.5<\/strong>\r\n\r\nOvarian_follicle<\/a> by TiagoLubiana<\/a> on Wikimedia Commons is used under a CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\n\r\n\r\nFigure 18.6.6<\/strong>\r\n\r\nHumanVulva-NewText-PhiloViv<\/a> by Amphis<\/a> (edited) on Wikimedia Commons is used under a CC BY-SA 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en) license. (Original \u00a0en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>en:user:PhiloVivero<\/a>)\r\n\r\nFigure 18.6.7<\/strong>\r\n\r\nVulva<\/a>\u00a0by OpenStax College<\/a> on Wikimedia Commons is used under a CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\nFigure 18.6.8<\/strong>\r\n\r\nBreast-Diagram<\/a> by Women's Health<\/a> (NCI\/ NIH) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/en:Public_domain).\r\n\r\n \r\n
\r\n\r\nReferences<\/span>\r\n\r\n<\/div>\r\n<\/section><\/div>\r\nBetts, J. G., Young, K.A., Wise, J.A., Johnson, E., Poe, B., Kruse, D.H., Korol, O., Johnson, J.E., Womble, M., DeSaix, P. (2013, June 19). Figure\u00a0<\/span>27.10<\/span>\u00a0<\/span>The vulva [digital image].\u00a0 In Anatomy and Physiology<\/em> (Section 27.2). OpenStax. https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/27-2-anatomy-and-physiology-of-the-female-reproductive-system<\/span><\/p>\r\n
Janux. (2015, January 10). Human physiology - Functional anatomy of the female reproductive system. YouTube. https:\/\/www.youtube.com\/watch?v=9rs2gNchQig&feature=youtu.be<\/p>\r\n
TED. (2019, March 22). The uncomplicated truth about women's sexuality | Sarah Barmak. YouTube.\u00a0 https:\/\/www.youtube.com\/watch?v=SkB4gG8ke7Q&feature=youtu.be<\/p>\r\n
Teixeira, J., Rueda, B.R., and Pru, J.K. (September 30, 2008). Figure 1 Uterine anatomy. In Uterine Stem Cells<\/em> (StemBook, ed.). The Stem Cell Research Community, StemBook, doi\/10.3824\/stembook.1.16.1, http:\/\/www.stembook.org<\/p>","rendered":"
<\/p>\n
Figure 18.6.1 Yep, that’s a vagina.<\/em><\/figcaption><\/figure>\n \nFertility Symbol<\/h1>\n<\/div>\n
The geometric design on the ancient stone carving in Figure 18.6.1 represents a powerful symbol of female fertility: the vagina<\/a>. The symbol is called yoni<\/em> in Hindu, and it reflects the value placed by Hindu culture on the ability of females to give birth. The vagina is one of several organs in the\u00a0female reproductive system.<\/p>\n
\nFemale Reproductive Organs<\/h1>\n<\/div>\n
The female reproductive system is made up of internal and external organs that function to produce haploid female gametes called ova (or oocytes), secrete female sex hormones (such as estrogen<\/a>), and carry and give birth to a fetus<\/a>. The internal female reproductive organs include the vagina, uterus<\/a>, oviducts<\/span><\/a><\/span>, and ovaries<\/a>. The external organs \u2014 collectively called the vulva<\/a> \u2014 include the clitoris<\/a> and labia<\/a>.<\/span><\/p>\n
The\u00a0vagina<\/a><\/strong> is an elastic, muscular canal leading from its opening in the vulva to the neck of the uterus, called the cervix<\/a>. It is about 7.5 cm (about 3 in) long at the front, and about 9 cm (3.5 in) long at the back. The vagina accommodates the penis and is the site where sperm<\/a> are usually ejaculated during sexual intercourse. In the context of pregnancy and natural (vaginal) childbirth, the vagina is referred to as the birth canal. In addition, it channels the flow of menstrual blood from the uterus<\/a>.<\/p>\n
Structure of the Vagina<\/h2>\n
Muscles and ligaments support the vagina within the pelvic cavity<\/a>. The vagina itself is made up of several layers of fibrous and muscular tissues and lined with mucous membranes<\/span><\/a><\/span>. Folds in the mucosa provide the vagina with extra surface area so it can stretch in both length and width during intercourse or childbirth. The elasticity of the vagina and the extra mucosa allow it to stretch to many times its normal diameter in order to deliver a baby.<\/span><\/p>\n
Bacteria\u00a0and\u00a0pH\u00a0in the Vagina<\/h2>\n
A healthy vagina<\/a> is home to many symbiotic<\/a>\u00a0bacteria<\/a> that help prevent pathogens (such as yeast) from colonizing the vagina. The pH<\/a> in the vagina is normally between 3.8 and 4.5, and this acidity also helps keep pathogenic microorganisms from colonizing it. The vagina constantly sheds its epithelium, so it is considered self-cleaning. As a consequence, there is no need for douching to clean it. Physicians actually discourage the practice, as it may upset the normal bacterial and pH balance in the vagina, although washing the vulva with a mild soap is good practice.<\/p>\n
\nUterus<\/h1>\n<\/div>\n
The\u00a0uterus<\/a><\/strong> (commonly called the womb) is a pear-shaped, muscular organ that is about 7.6 cm (about 3 in) long. It is located above the vagina and behind the bladder<\/a> in the centre of the pelvis. The position of the uterus in the pelvis is stabilized by several ligaments and bands of supportive tissue. The uterus is where a fetus develops during gestation, and the organ provides mechanical protection and support for the developing offspring. Contractions of the muscular wall of the uterus are responsible for pushing the fetus out of the uterus during childbirth.<\/p>\n
Figure 18.6.2 The cervix of the uterus opens into the vagina. The body of the uterus lies above the cervix.<\/em><\/figcaption><\/figure>\n Parts of the Uterus<\/h2>\n
As shown in Figure 18.6.2, the lower end of the uterus forms the cervix<\/a>,<\/strong> which is also called the neck of the uterus. The cervix is about 2.5 cm (almost 1 in) long and protrudes downward into the vagina. A small canal runs the length of the cervix, connecting the uterine cavity with the lumen of the vagina. This allows semen deposited in the vagina to enter the uterus, and a baby to pass from the uterus into the vagina during birth. Glands in the cervix secrete mucus that varies in water content and thickness, so it can function either as a barrier to keep microorganisms<\/span><\/a><\/span>\u00a0out of the uterus during\u00a0pregnancy, or as a transport medium to help\u00a0sperm\u00a0enter the uterus around the time of ovulation<\/a>. The rest of the uterus above the cervix is called the body of the uterus. The upper end of the uterus is connected with the two oviduct<\/span>s<\/span><\/a><\/span>.<\/span><\/p>\n
Tissues of the Uterus<\/h2>\n
As indicated in Figure 18.6.3, the uterus consists of three tissue layers, called the endometrium, myometrium, and perimetrium.<\/p>\n
- \n
- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0myometrium<\/a><\/strong>\u00a0is the middle layer of the uterus. It consists mostly of a thick layer of smooth muscle tissue. Powerful contractions of the smooth muscle allow the uterus to contract and expel an infant during childbirth.<\/li>\n
- The\u00a0perimetrium<\/a><\/strong>\u00a0is the outermost layer of the uterus. It covers\u00a0the\u00a0outer surface of the uterus. This layer actually consists of two layers of epithelium that secrete fluid into the space between them. The fluid allows for small movements of the uterus within the pelvis, without\u00a0causing it to rub\u00a0against other organs.<\/li>\n<\/ul>\n
Figure 18.6.3 The thick walls of the uterus are composed of layers of tissues known as endometrium, myometrium, and perimetrium (not shown in this image).<\/em><\/figcaption><\/figure>\n \nOviducts<\/span><\/p>\n<\/div>\n
The\u00a0oviduct<\/strong>s<\/strong><\/a><\/strong> (often referred to as Fallopian tubes) are two thin tubes that lie between the ovaries<\/a> and the uterus<\/a>. The oviducts are not attached to the ovaries, but their broad upper ends \u2014 called infundibula \u2014 lie very close to the ovaries. The infundibula also have fringe-like extensions called fimbriae<\/a> that move in a waving motion to help guide eggs from the ovaries into the oviducts. The lower ends of the oviducts are attached to the upper part of the body of the uterus<\/a> on either side of the body. They open into the uterus.<\/span><\/p>\n
The oviducts are made up of multiple tissue layers. The innermost layer consists of mucosal epithelium. The epithelium is covered with cilia<\/a>, which can move in a sweeping motion to help ova move through the tube from the ovary to the uterus. In between the ciliated cells of the epithelium are cells that secrete a fluid called tubular fluid. This fluid contains nutrients for sperm, ova, and zygotes. The secretions in tubular fluid also remove certain molecules from the plasma membrane<\/a> of sperm so they are better able to penetrate an egg. Other layers of the oviducts consist of connective tissue and smooth muscle. Contractions of the smooth muscle<\/a> allow peristalsis<\/a> to help move eggs through the tubes.<\/p>\n
\nOvaries<\/h1>\n<\/div>\n
Like the testes<\/a> in males, the\u00a0ovaries<\/a><\/strong>\u00a0in females are gonads<\/span><\/a><\/span>\u00a0that produce gamete<\/span>s<\/span><\/a><\/span> and secrete sex hormones<\/a>. The gametes produced by the ovaries are called ova<\/a>, or oocytes. The main sex hormone secreted by the ovaries is estrogen<\/a>. The position of the paired ovaries relative to the other reproductive system organs is shown in Figure 18.6.4. Each ovary lies along one side of the uterus and is about 4 cm (a little more than 1.5 in) long. Fibrous ligaments attach one end of each ovary to its nearby oviduct and the other and to its side of the uterus. These ligaments keep the ovaries in place within the pelvis.<\/span><\/p>\n
Figure 18.6.4 The placement of the two ovaries within the pelvis allows eggs from each ovary to enter a Fallopian tube and travel to the uterus.<\/em><\/figcaption><\/figure>\n Ovarian Follicles<\/h2>\n
The ovary consists of two main layers, called the ovarian medulla (the inner layer) and the ovarian cortex (the outer layer). The ovary also contains\u00a0blood<\/a>\u00a0and lymphatic vessels. The ovarian cortex consists primarily of the functional units of the ovaries, which are called\u00a0ovarian follicle<\/strong>s<\/strong><\/a>.<\/strong> The follicles are nests of epithelial cells, within each of which is an ovum. The photomicrograph in Figure 18.6.5 shows an ovarian follicle and the developing ovum inside it. If an ovum and follicle complete maturation, the follicle ruptures and the ovum is released from the ovary. This event is called ovulation<\/a>.<\/span><\/p>\n
Figure 18.6.5 An ovum within its nest of follicular cells inside an ovary.<\/em><\/figcaption><\/figure>\n Ova in the Ovaries<\/h2>\n
Whereas the male testes<\/a> produce sperm continuously after\u00a0puberty<\/a>, the female ovary already contains all the ova it will ever produce by the time a female is born. At birth, a baby girl\u2019s ovaries<\/a> contain at least a million eggs, each of which is contained within a follicle<\/a>. Only about 500 of these eggs will eventually mature and be ovulated. This process starts at puberty and typically continues at monthly intervals until menopause<\/a> occurs around age 52. The remaining eggs never mature, and their number declines as the woman ages. By menopause, a woman\u2019s reserve of eggs is nearly depleted, and ovulation<\/a> no longer occurs.<\/p>\n
\nVulva<\/h1>\n<\/div>\n
The\u00a0vulva<\/a><\/strong> is a general term for all of the external female reproductive organs. The vulva includes the clitoris, labia, and external openings for the urethra and vagina.<\/p>\n
Labia<\/h2>\n
The\u00a0labia<\/a><\/strong> (singular, labium) refer to the \u201clips\u201d of the vulva, which are folds of tissue that contain and protect the other, more delicate structures of the vulva (as shown in Figure 18.6.6). There are two pairs of labia: the outer and larger labia majora, and the inner and smaller labia minora. The labia minora contain numerous sebaceous glands. These glands release secretions that help lubricate the labia and vulvar area.<\/p>\n
Figure 18.6.6 The vulva includes the external features of the female reproductive system including the labia, clitoris and clitoral hood, and the openings from the urethra and to the vagina.<\/em><\/figcaption><\/figure>\n Clitoris<\/h2>\n
The\u00a0clitoris<\/a>,<\/strong>\u00a0is located at the front of the vulva<\/a> where the labia minora meet. The visible portion of the clitoris is called the glans clitoris. It is roughly the size and shape of a pea. It is highly sensitive, because it contains many nerve endings. A hood of tissue called the clitoral hood (shown in Figure 18.6.5 above), or prepuce, normally covers and protects the clitoris. The clitoris is the homologue to the male penis, and they both contain spongy tissue.\u00a0\u00a0Stimulation of the glans clitoris during sexual activity generally results in sexual arousal in females, and may lead to orgasm.<\/span> The glans clitoris is the only part of the overall clitoris visible externally, but this spongy tissue extends down either side of the openings to the urethra and vagina, as seen in Figure 18.6.7.<\/span><\/p>\n
Figure 18.6.7 While the glans clitoris is the only externally visible part of the clitoris, this spongy tissue extends dorsally into the corpus cavernosum, which flanks the left and right sides of the opening to the vagina.<\/em><\/figcaption><\/figure>\n Other Vulvar Structures<\/h2>\n
The area between the two labia minora is called the vestibule of the vulva. Both the urethra<\/a> and vagina<\/a> have openings to the outside of the body in the vestibule. As you can see in Figure 18.6.7 above, the urethral opening (or meatus) is located just in front of, and is much smaller than, the vaginal opening. Both openings are protected by the labia. Two glands \u2014 called Bartholin\u2019s glands \u2014 open on either side of the vaginal opening. These glands secrete mucus and a vaginal and vulvar lubricant.<\/p>\n
\nBreasts<\/h1>\n<\/div>\n
- The placenta<\/a><\/strong>\u00a0is a temporary organ that consists of a mass of maternal and fetal\u00a0blood vessels\u00a0through which the mother\u2019s and fetus\u2019s\u00a0blood\u00a0exchange substances.<\/li>\n
- The\u00a0endometrium<\/a><\/strong> is the innermost tissue layer of the uterus. It consists of epithelial tissue, including mucous membranes. This layer thickens during each menstrual cycle and, unless an egg is fertilized, sloughs off during the following menstrual period. If an ovum is fertilized, the thickened endometrium is maintained by hormones and provides nourishment to the embryo. As gestation progresses, the endometrium develops into the maternal portion of the placenta.<\/li>\n
![1024px-Cattien_stone_yoni<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Cattien_stone_yoni.png\"){kind=link}
![1000px-Gray1167.svg<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Gray1167.svg\"){kind=link}
![Uterine_anatomy.<\/a> from](\"https:\/\/commons.wikimedia.org\/wiki\/File:Uterine_anatomy..jpg\"){kind=link}
![Uterine Stem cells<\/a> by](\"https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK27042\/bin\/Teixeira01.jpg\"){kind=link}
![Sites_of_tubo_ovarian_abscess<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Sites_of_tubo_ovarian_abscess.PNG\"){kind=link}
![Ovarian_follicle<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Ovarian_follicle.png\"){kind=link}
![HumanVulva-NewText-PhiloViv<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:HumanVulva-NewText-PhiloViv.jpg#file\"){kind=link}
![en:Image:HumanVulva-NoText-PhiloVivero.jpg<\/a> by <\/span>](\"https:\/\/en.wikipedia.org\/wiki\/Image:HumanVulva-NoText-PhiloVivero.jpg\"){kind=link}
![Vulva<\/a>\u00a0by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Figure_28_02_02.jpg\"){kind=link}
![Breast-Diagram<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Breast-Diagram.gif\"){kind=link}