A \u201cMitey\u201d Monster<\/h1>\r\n<\/div>\r\nThe scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can't eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.\r\n\r\nAsthma<\/h1>\r\n<\/div>\r\n \r\n\r\n[caption id=\"attachment_4349\" align=\"alignright\" width=\"475\"]![\"13.5.2](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Asthma_attack-illustration_NIH-2.jpg\")
Figure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em>[\/caption]\r\n\r\n[pb_glossary id=\"4348\"]Asthma[\/pb_glossary]<\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.\r\n\r\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.\r\n\r\n[caption id=\"attachment_4350\" align=\"alignright\" width=\"234\"]![\"13.5.3](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/asthma-inhaler-2.jpg\")
Figure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em>[\/caption]\r\n\r\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.\r\n\r\nPneumonia<\/h1>\r\n<\/div>\r\nAnother common inflammatory disease of the respiratory tract is\u00a0[pb_glossary id=\"4351\"]pneumonia[\/pb_glossary].<\/strong> In pneumonia, inflammation affects primarily the [pb_glossary id=\"4311\"]alveoli[\/pb_glossary], which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.\r\n\r\n[caption id=\"attachment_4352\" align=\"aligncenter\" width=\"431\"]![\"13.5.4](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Lobar_pneumonia_illustrated-2.jpg\")
Figure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em>[\/caption]\r\n\r\nPneumonia often develops as a consequence of an [pb_glossary id=\"4290\"]upper respiratory tract[\/pb_glossary] infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary]\u00a0or [pb_glossary id=\"4283\"]viruses<\/span>[\/pb_glossary]<\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as [pb_glossary id=\"4348\"]asthma[\/pb_glossary], a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span>\r\n\r\n[pb_glossary id=\"4353\"]Vaccines<\/span>[\/pb_glossary]<\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span>\r\n\r\nChronic Obstructive Pulmonary Disease<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.\r\n\r\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.\r\n\r\n[caption id=\"attachment_4355\" align=\"aligncenter\" width=\"389\"]![\"13.5.5](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Blausen_0343_Emphysema-e1591978243828-2.png\")
Figure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em>[\/caption]\r\n\r\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.\r\n\r\nLung\u00a0Cancer<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary]<\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of [pb_glossary id=\"3928\"]metastasis[\/pb_glossary] from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0[pb_glossary id=\"277\"]DNA[\/pb_glossary]\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.\r\n\r\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.\r\n\r\nMost cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.\r\n\r\nFeature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"]![\"15.5.6](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Airway_obstruction-2.png\")
Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"]![\"15.5.7](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Depiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine-2.png\")
Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\n![\"13.5.1](\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2019\/06\/House_Dust_Mite-2.jpg\")
Figure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
Asthma<\/h1>\r\n<\/div>\r\n \r\n\r\n[caption id=\"attachment_4349\" align=\"alignright\" width=\"475\"] Figure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em>[\/caption]\r\n\r\n[pb_glossary id=\"4348\"]Asthma[\/pb_glossary]<\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.\r\n\r\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.\r\n\r\n[caption id=\"attachment_4350\" align=\"alignright\" width=\"234\"] Figure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em>[\/caption]\r\n\r\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.\r\n\r\nPneumonia<\/h1>\r\n<\/div>\r\nAnother common inflammatory disease of the respiratory tract is\u00a0[pb_glossary id=\"4351\"]pneumonia[\/pb_glossary].<\/strong> In pneumonia, inflammation affects primarily the [pb_glossary id=\"4311\"]alveoli[\/pb_glossary], which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.\r\n\r\n[caption id=\"attachment_4352\" align=\"aligncenter\" width=\"431\"] Figure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em>[\/caption]\r\n\r\nPneumonia often develops as a consequence of an [pb_glossary id=\"4290\"]upper respiratory tract[\/pb_glossary] infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary]\u00a0or [pb_glossary id=\"4283\"]viruses<\/span>[\/pb_glossary]<\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as [pb_glossary id=\"4348\"]asthma[\/pb_glossary], a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span>\r\n\r\n[pb_glossary id=\"4353\"]Vaccines<\/span>[\/pb_glossary]<\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span>\r\n\r\nChronic Obstructive Pulmonary Disease<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.\r\n\r\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.\r\n\r\n[caption id=\"attachment_4355\" align=\"aligncenter\" width=\"389\"] Figure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em>[\/caption]\r\n\r\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.\r\n\r\nLung\u00a0Cancer<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary]<\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of [pb_glossary id=\"3928\"]metastasis[\/pb_glossary] from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0[pb_glossary id=\"277\"]DNA[\/pb_glossary]\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.\r\n\r\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.\r\n\r\nMost cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.\r\n\r\nFeature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"] Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"] Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
Pneumonia<\/h1>\r\n<\/div>\r\nAnother common inflammatory disease of the respiratory tract is\u00a0[pb_glossary id=\"4351\"]pneumonia[\/pb_glossary].<\/strong> In pneumonia, inflammation affects primarily the [pb_glossary id=\"4311\"]alveoli[\/pb_glossary], which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.\r\n\r\n[caption id=\"attachment_4352\" align=\"aligncenter\" width=\"431\"] Figure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em>[\/caption]\r\n\r\nPneumonia often develops as a consequence of an [pb_glossary id=\"4290\"]upper respiratory tract[\/pb_glossary] infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0[pb_glossary id=\"2588\"]bacteria[\/pb_glossary]\u00a0or [pb_glossary id=\"4283\"]viruses<\/span>[\/pb_glossary]<\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as [pb_glossary id=\"4348\"]asthma[\/pb_glossary], a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span>\r\n\r\n[pb_glossary id=\"4353\"]Vaccines<\/span>[\/pb_glossary]<\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span>\r\n\r\nChronic Obstructive Pulmonary Disease<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.\r\n\r\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.\r\n\r\n[caption id=\"attachment_4355\" align=\"aligncenter\" width=\"389\"] Figure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em>[\/caption]\r\n\r\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.\r\n\r\nLung\u00a0Cancer<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary]<\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of [pb_glossary id=\"3928\"]metastasis[\/pb_glossary] from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0[pb_glossary id=\"277\"]DNA[\/pb_glossary]\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.\r\n\r\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.\r\n\r\nMost cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.\r\n\r\nFeature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"] Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"] Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
Chronic Obstructive Pulmonary Disease<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.\r\n\r\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.\r\n\r\n[caption id=\"attachment_4355\" align=\"aligncenter\" width=\"389\"] Figure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em>[\/caption]\r\n\r\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.\r\n\r\nLung\u00a0Cancer<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary]<\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of [pb_glossary id=\"3928\"]metastasis[\/pb_glossary] from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0[pb_glossary id=\"277\"]DNA[\/pb_glossary]\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.\r\n\r\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.\r\n\r\nMost cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.\r\n\r\nFeature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"] Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"] Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
Lung\u00a0Cancer<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary]<\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of [pb_glossary id=\"3928\"]metastasis[\/pb_glossary] from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0[pb_glossary id=\"277\"]DNA[\/pb_glossary]\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.\r\n\r\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.\r\n\r\nMost cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.\r\n\r\nFeature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"] Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"] Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
Feature: My\u00a0Human Body<\/h1>\r\n<\/div>\r\nDo you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0[pb_glossary id=\"4357\"]Sleep apnea[\/pb_glossary]<\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.\r\n\r\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.\r\n\r\n[caption id=\"attachment_4358\" align=\"aligncenter\" width=\"612\"] Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em>[\/caption]\r\n\r\n[caption id=\"attachment_4359\" align=\"alignright\" width=\"473\"] Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em>[\/caption]\r\n\r\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span>\r\n\r\n\r\n13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
13.5 Summary<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\n \t- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/a> on Wikimedia Commons is used under a CC BY-SA 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0) license.\r\nReferences<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\nFigure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n\nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\nFigure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\nAsthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\nAsthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\nFigure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\nThere is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\nFigure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\nPneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\nVaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\nCOPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\nFigure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\nSmoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\nThe major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\nFigure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\nFigure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\nFigure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\nTreatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n\n\n\n13.5 Summary<\/span><\/h1>\n<\/header>\n\n\n- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
\n13.5 Review Questions<\/span><\/h1>\n<\/header>\n\n\n- \n\n
- \r\n \t
- [pb_glossary id=\"4348\"]Asthma [\/pb_glossary]is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\r\n \t
- [pb_glossary id=\"4351\"]Pneumonia[\/pb_glossary] is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\r\n \t
- [pb_glossary id=\"4354\"]Chronic obstructive pulmonary disease[\/pb_glossary] (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\r\n \t
- [pb_glossary id=\"4356\"]Lung cancer[\/pb_glossary] is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n
\r\n 13.5 Review Questions<\/span><\/h1>\r\n<\/header>\r\n
\r\n- \r\n \t
- [h5p id=\"610\"]<\/li>\r\n \t
- How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled?.<\/li>\r\n \t
- How can pneumonia be prevented? How is it treated?<\/li>\r\n \t
- What is the difference between primary and secondary lung cancer? What is the major cause of primary lung cancer? Discuss lung cancer as a cause of death. How is lung cancer treated?<\/li>\r\n \t
- What is the difference between how COPD and pneumonia affect the alveoli?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
\r\n 13.5 Explore More<\/span><\/h1>\r\n<\/header>\r\n
\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=emb_logo\r\nShaf Keshavjee at TEDMED 2010.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=emb_logo\r\n
Immunology of the Lung, Nature Video, 2014.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI\r\n
What you should know about vaping and e-cigarettes, TEDMED, 2019.<\/p>\r\nhttps:\/\/www.youtube.com\/watch?v=aQsOmGflf1o\r\n
What your breath could reveal about your health | Julian Burschka, TED, 2019.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
Attributions<\/h2>\r\nFigure 13.5.1<\/strong>\r\n\r\nHouse_Dust_Mite<\/a> by Employee of US Food and Drug Administration<\/a> (archived) on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.2<\/strong>\r\n\r\nAsthma_attack-illustration_NIH<\/a> by National Heart, Lung, Blood Institute<\/a>\/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.3<\/strong>\r\n\r\nasthma-inhaler<\/a> by Anthony Poynton on Public Domain Pictures<\/a> is used under a CC0 1.0<\/a>\u00a0 Universal Public Domain Dedication License (https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/).\r\n\r\nFigure 13.5.4<\/strong>\r\n\r\nLobar_pneumonia_illustrated<\/a> by National Heart, Lung and Blood Institute<\/a> \/ U.S. National Institute of Health on Wikimedia Commons is in the public domain<\/a> (https:\/\/en.wikipedia.org\/wiki\/Public_domain).\r\n\r\nFigure 13.5.5<\/strong>\r\n\r\nBlausen_0343_Emphysema<\/a> by Blausen Medical Communications, Inc.<\/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 13.5.6<\/strong>\r\n\r\nAirway_obstruction<\/a> by Drcamachoent<\/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 13.5.7<\/strong>\r\n\r\nDepiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by https:\/\/www.myupchar.com\/en<\/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
References<\/h2>\r\n
Centers for Disease Control and Prevention (CDC). (2020). Travel: Pneumococcal disease (streptococcus pneumoniae) [online article]. U.S. Department of Health & Human Services. https:\/\/wwwnc.cdc.gov\/travel\/diseases\/pneumococcal-disease-streptococcus-pneumoniae<\/p>\r\n
Nature Video. (2014, December 15). Immunology of the lung. YouTube. https:\/\/www.youtube.com\/watch?v=rgphaHmAC_A&feature=youtu.be<\/p>\r\n
TED. (2019, February 25). What your breath could reveal about your health | Julian Burschka. YouTube. https:\/\/www.youtube.com\/watch?v=aQsOmGflf1o&feature=youtu.be<\/p>\r\nTEDMED. (2010, December 7). Shaf Keshavjee at TEDMED 2010. YouTube. https:\/\/www.youtube.com\/watch?v=T2EmuyHoMAI&feature=youtu.be\r\n
TEDMED. (2019, May 15). What you should know about vaping and e-cigarettes. YouTube. https:\/\/www.youtube.com\/watch?v=W1rF2oFnfYI&feature=youtu.be<\/p>\r\n
<\/p>","rendered":"
<\/p>\n
Figure 13.5.1 This is “mitey” scary looking.<\/em><\/figcaption><\/figure>\n \nA \u201cMitey\u201d Monster<\/h1>\n<\/div>\n
The scary beast in Figure 13.5.1 is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It\u2019s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it\u2019s obviously shown greatly enlarged above. If you think you can get rid of dust mites in your home by frequent and thorough cleaning, think again. There may be thousands of dust mites in just one gram of dust! Regardless of how clean you keep your house, you can’t eliminate dust mites entirely. So why even bother trying? The feces of dust mites contain proteins that are a common trigger of asthma attacks.<\/p>\n
\nAsthma<\/h1>\n<\/div>\n
<\/p>\n
Figure 13.5.2 During an asthma attack, airways narrow and may become clogged with mucus, making breathing difficult.<\/em><\/figcaption><\/figure>\n Asthma<\/a><\/strong> is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. As you can see in Figure 13.5.2, this causes swelling and narrowing of the airways, often accompanied by excessive mucus production. Symptoms of asthma include difficulty breathing, coughing, wheezing, shortness of breath, and chest tightness. Some people with asthma rarely experience symptoms, and then usually only in response to certain triggers in the environment. Other people may have symptoms almost all of the time.<\/p>\n
Asthma is thought to be caused by a combination of genetic and environmental factors. A person with a family history of asthma is more likely to develop the disease. Dozens of genes have been found to be associated with asthma, many of which are related to the immune system. Additional risk factors include obesity and sleep apnea. Environmental factors trigger asthma attacks in people who have a genetic predisposition to the disease. Besides dust mite feces, triggers may include other allergens (such as pet dander, cockroaches, and mold), certain medications including aspirin, air pollution, and stress. Symptoms tend to be worse at night and early in the morning. They may also worsen during upper respiratory tract infections, strenuous exercise, or when the airways are exposed to cold air.<\/p>\n
Figure 13.5.3 Use of inhaled bronchodilators (medications which cause the bronchi to expand) can help patients manage the long-term effects of living with asthma.<\/em><\/figcaption><\/figure>\n There is no cure for asthma at present, but the symptoms of asthma attacks usually can be reversed with the use of inhaled medications called bronchodilators (as shown in Figure 13.5.3). These medications soothe the constricted air passages and help to re-expand them, making breathing easier. The medications usually start to take effect almost immediately. Other medications can be taken for long-term control of the disease. These medications help prevent asthma attacks from occurring. Corticosteroids are generally considered the most effective treatment for long-term control. Another way to prevent asthma attacks is by avoiding triggers whenever possible.<\/p>\n
\nPneumonia<\/h1>\n<\/div>\n
Another common inflammatory disease of the respiratory tract is\u00a0pneumonia<\/a>.<\/strong> In pneumonia, inflammation affects primarily the alveoli<\/a>, which are the tiny air sacs of the lungs. Inflammation causes some of the alveoli to become filled with fluid so that gas exchange cannot occur, as you can see illustrated in Figure 13.5.4. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fever.<\/p>\n
Figure 13.5.4 Fluid-filled alveoli characteristic of pneumonia inhibit normal gas exchange with the blood.<\/em><\/figcaption><\/figure>\n Pneumonia often develops as a consequence of an upper respiratory tract<\/a> infection (such as the common cold or flu), especially in the very young and the elderly. It is usually caused by\u00a0bacteria<\/a>\u00a0or viruses<\/span><\/a><\/span>, although some cases may be caused by other microorganisms, such as\u00a0fungi. The majority of cases are caused by just a few pathogens, the most common being the bacterium\u00a0<\/span>Streptococcus pneumoniae<\/a>.<\/em>\u00a0Pneumonia is more likely to develop in people who have other lung diseases, such as asthma<\/a>, a history of smoking,\u00a0heart\u00a0failure, or a weakened immune system.<\/span><\/p>\n
Vaccines<\/span><\/a><\/span>\u00a0are available to prevent certain types of bacterial and viral pneumonia, including pneumonia caused by\u00a0<\/span>Streptococcus pneumoniae. <\/em>Treatment of pneumonia depends on the cause. For example, if the disease is caused by\u00a0bacteria, antibiotics are generally prescribed. In cases of severe pneumonia, hospitalization and supplemental oxygen may be required.<\/span><\/p>\n
\nChronic Obstructive Pulmonary Disease<\/h1>\n<\/div>\n
Chronic obstructive pulmonary disease<\/a> (COPD)<\/strong> is a lung disease characterized by chronic poor airflow due to increasing in-elasticity of lung tissue and breakdown of the walls of the alveoli. The main symptoms include shortness of breath and a cough that produces phlegm. These symptoms are usually present for a long period of time, and typically become worse over time. Eventually, walking up stairs and similar activities become difficult because of shortness of breath.<\/p>\n
COPD formerly was referred to as chronic bronchitis or emphysema. Now, the term\u00a0chronic bronchitis<\/em>\u00a0is used to refer to the symptoms of COPD, and the term\u00a0emphysema<\/em> is used to refer to the lung changes that occur with COPD. Some of these lung changes are shown in Figure 13.5.5 below. They include a breakdown of connective tissues that reduces the number and elasticity of alveoli. As a result, the patient can no longer fully exhale air from the lungs, so air becomes trapped in the lungs. Gas exchange is hampered and may lead to low oxygen levels, as well as too much carbon dioxide in the blood.<\/p>\n
Figure 13.5.5 The physiological changes that occur with COPD include a breakdown of alveolar walls, reducing the surface area for gas exchange.<\/em><\/figcaption><\/figure>\n Smoking tobacco and vaping are the major cause of COPD, with a number of other factors such as air pollution and genetics playing smaller roles. Of people who are life-long smokers, about half will eventually develop COPD. Exposure to secondhand smoke in nonsmokers also increases the risk of COPD, and accounts for about 20 per cent of cases.\u00a0 Most cases of COPD could have been prevented by never smoking or vaping. In people who have already been diagnosed with COPD, cessation of smoking or vaping can slow down the rate at which COPD worsens. People with COPD may be treated with supplemental oxygen and inhaled bronchodilators. These treatments may reduce the symptoms, but there is no cure for COPD except \u2014 in very severe cases \u2014 lung transplantation.<\/p>\n
\nLung\u00a0Cancer<\/h1>\n<\/div>\n
Lung cancer<\/a><\/strong>\u00a0is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. The tumor may arise directly from lung tissue (primary lung cancer), or as a result of metastasis<\/a> from cancer in another part of the body (secondary lung cancer). Primary lung cancer may also metastasize and spread to other parts of the body. Lung cancer develops\u00a0after\u00a0genetic damage to\u00a0DNA<\/a>\u00a0that affects the normal functions of the cell. As more damage accumulates, the risk of cancer increases. The most common symptoms of lung cancer include coughing (especially coughing up blood), wheezing, shortness of breath, chest pain, and\u00a0weight\u00a0loss.<\/p>\n
The major cause of primary lung cancer is tobacco use, which accounts for about 85 per cent of cases. Cigarette smoke contains numerous cancer-causing chemicals. Besides smoking, other potential causes of lung cancer include exposure to radon gas, asbestos, secondhand smoke, or other air pollutants. When tobacco smoking is combined with another risk factor (such as exposure to radon or asbestos), the risk of lung cancer is heightened. People who have close biological relatives with lung cancer are also at increased risk of developing the disease.<\/p>\n
Most cases of lung cancer cannot be cured. In many people, the cancer has already spread beyond the original site by the time they have symptoms and seek medical attention. About ten per cent of people with lung cancer do not have symptoms when they are diagnosed, and the cancers are found when they have a chest X-ray for another problem. In part because of its typically late diagnosis, lung cancer is the most common cause of cancer-related death in men, and the second most common cause in women (after breast cancer). Approximately 21,000 Canadians die from lung cancer each year.\u00a0 Common treatments for lung cancer include surgical removal of the tumor, radiation therapy, chemotherapy, or some combination of these three types of treatment.<\/p>\n
\nFeature: My\u00a0Human Body<\/h1>\n<\/div>\n
Do you \u2014 or someone you love\u00a0\u2014\u00a0snore? Snoring may be more than just an annoyance. It may also be a sign of a potentially dangerous and common disorder known as sleep apnea.\u00a0Sleep apnea<\/a><\/strong>\u00a0is characterized by pauses in breathing that occur most often because of physical blockage to airflow during sleep. When breathing is paused, carbon dioxide builds up in the bloodstream. The higher-than-normal level of carbon dioxide in the\u00a0blood\u00a0causes the respiratory centers in the brain to wake the person enough to start breathing normally. This reduces the carbon dioxide level, and the person falls back asleep. This occurs repeatedly throughout the night, causing serious disruption in sleep. Most people with sleep apnea are unaware that they have the disorder, because they don\u2019t\u00a0wake up\u00a0fully enough to remember the repeated awakenings throughout the night. Instead, sleep apnea is more commonly recognized by other people who witness the episodes.<\/p>\n
Figure 13.5.6 below shows how sleep apnea typically occurs. The muscle tone of the body normally relaxes during sleep, allowing the soft tissues in the throat to collapse and block the airway. The relaxation of muscles may be exacerbated by the use of alcohol, tranquilizers, or muscle relaxants. The risk of sleep apnea is greater in people who are overweight, smoke tobacco, or have diabetes. The disorder is also more likely to occur in older people and males. Common symptoms of sleep apnea include loud snoring, restless sleep, and daytime sleepiness and fatigue. Daytime sleepiness, in turn, increases the risk of driving and work-related accidents. Continued sleep deprivation may cause moodiness and belligerence. Lack of adequate oxygen to the body because of sleep apnea may also lead to other health problems, including fatty liver diseases and high blood pressure. Symptoms of sleep apnea may be present for years \u2014 or even decades \u2014 until (and if) a diagnosis is finally made.<\/p>\n
Figure 13.5.6 Sleeping on one\u2019s back may increase the risk of the airway becoming temporarily blocked during sleep, resulting in sleep apnea.<\/em><\/figcaption><\/figure>\n Figure 13.5.7 The use of a CPAP machine can be used to treat sleep apnea.<\/em><\/figcaption><\/figure>\n Treatment of sleep apnea may include avoiding alcohol, quitting smoking, or losing weight. Elevating the upper body during sleep or sleeping on one\u2019s side may help prevent airway collapse in many people with sleep apnea. Another type of treatment is the use of an oral device that shifts the lower jaw forward to help keep the airway open during sleep. The most common treatment for moderate to severe sleep apnea is the use of CPAP (c<\/strong>onstant p<\/strong>ositive a<\/strong>ir p<\/strong>ressure), which keeps the airway open by means of pressurized air during sleep. In this treatment, the person typically wears a plastic facial mask that is connected by a flexible tube to a small bedside CPAP machine as shown to the right in Figure 13.5.7<\/span>. Although CPAP is effective, long-term compliance is often poor, because patients find the mask uncomfortable or they experience unpleasant side effects, such as dry mouth and nose. A more extreme form of treatment is surgery to remove some of the tissues \u2014 such as the tonsils or part of the soft palate \u2014 that tend to collapse and block the airway in people with sleep apnea.<\/span><\/p>\n
\n\n\n 13.5 Summary<\/span><\/h1>\n<\/header>\n
\n- \n
- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Chronic obstructive pulmonary disease<\/a> (COPD) is a lung disease characterized by chronic poor airflow, which causes shortness of breath and a productive cough. It is caused most often by tobacco smoking, which leads to breakdown of connective tissues in the lungs. Alveoli are reduced in number and elasticity, making it impossible to fully exhale air from the lungs. There is no cure for COPD, but stopping smoking may reduce the rate at which COPD worsens.<\/li>\n
- Lung cancer<\/a> is a malignant tumor characterized by uncontrolled cell growth in tissues of the lung. It results from accumulated\u00a0DNA\u00a0damage, most often caused by tobacco smoking. Lung cancer is typically diagnosed late, so most cases cannot be cured. It may be treated with surgery, chemotherapy, and\/or radiation therapy.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n
\n\n 13.5 Review Questions<\/span><\/h1>\n<\/header>\n
\n- \n
- \n\n
- Pneumonia<\/a> is a common inflammatory disease of the respiratory tract, in which inflammation affects primarily the alveoli, which become filled with fluid that inhibits\u00a0gas exchange. Most cases of pneumonia are caused by viral or bacterial infections. Vaccines are available to prevent pneumonia. Treatment often includes prescription antibiotics.<\/li>\n
- Asthma <\/a>is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms. Asthma is thought to be caused by a combination of genetic and environmental factors. Asthma attacks are triggered by allergens,\u00a0air pollution, or other factors.<\/li>\n
![House_Dust_Mite<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:House_Dust_Mite.jpg\"){kind=link}
![Asthma_attack-illustration_NIH<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Asthma_attack-illustration_NIH.jpg\"){kind=link}
![Lobar_pneumonia_illustrated<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Lobar_pneumonia_illustrated.jpg\"){kind=link}
![Blausen_0343_Emphysema<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Blausen_0343_Emphysema.png\"){kind=link}
![Airway_obstruction<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Airway_obstruction.png\"){kind=link}
![Depiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine<\/a> by](\"https:\/\/commons.wikimedia.org\/wiki\/File:Depiction_of_a_Sleep_Apnea_patient_using_a_CPAP_machine.png\"){kind=link}