Chapter 13 Answers: Respiratory System

13.2  Structure and Function of the Respiratory System: Review Questions and Answers

1. Self-marking
2. What is respiration, as carried out by the respiratory system? Name the two subsidiary processes it involves. Respiration is the process in which oxygen moves from the outside air into the body and carbon dioxide and other waste gases move from inside the body into the outside air. It involves ventilation and gas exchange.
3. Describe the respiratory tract. The respiratory tract is a continuous system of passages that carry air into and out of the body. It has two major divisions: the upper respiratory tract and the lower respiratory tract.
4. Identify the organs of the upper respiratory tract. What are their functions? The organs of the upper respiratory tract are the nasal cavity, pharynx, and larynx. All of these organs are involved in conduction, or the movement of air into and out of the body. Incoming air is also cleaned, humidified, and warmed as it passes through the organs of the upper respiratory tract. The larynx contains the vocal cords, which have the function of producing vocal sounds.
5. List the organs of the lower respiratory tract. Which organs are involved only in conduction? The organs of the lower respiratory tract are trachea, bronchi and bronchioles, and the lungs. The trachea, bronchi, and bronchioles are involved in conduction.
6. Where does gas exchange take place? Gas exchange takes place only in the lungs. Lung tissue consists mainly of tiny air sacs called alveoli, which is where gas exchange takes place between air in the alveoli and the blood in capillaries surrounding them.
7. How does the respiratory system protect itself from potentially harmful substances in the air? The respiratory system protects itself from potentially harmful substances in the air by the mucociliary escalator. This includes mucus-producing cells, which trap particles and pathogens in incoming air. It also includes tiny hair-like cilia that continually move to sweep the mucus and trapped debris away from the lungs and toward the outside of the body.
8. Explain how the rate of breathing is controlled. The rate of breathing is controlled by the nervous system. The level of carbon dioxide in the blood is monitored by cells in the brain. If the level becomes too high, it triggers a faster rate of breathing, which lowers the level to the normal range. The opposite occurs if the level becomes too low.
9. Why does the respiratory system need the cardiovascular system to help it perform its main function of gas exchange? The respiratory system exchanges gases with the outside air, but it needs the cardiovascular system to carry the gases to and from cells throughout the body.
10. Describe two ways in which the body prevents food from entering the lungs. Answers may vary. Sample answer: The epiglottis at the entrance to the larynx closes when swallowing occurs, preventing food from entering the larynx and going deeper into the respiratory tract towards the lungs. Also, if food does start to enter the larynx, it irritates it, which triggers a cough reflex. This usually expels the food out of the larynx and into the throat.
11. What is the relationship between respiration and cellular respiration? Answers may vary. Sample answer: Cellular respiration is the intracellular process by which cells produce energy. Aerobic cellular respiration requires oxygen to “burn” glucose for energy and produces carbon dioxide as a waste product. Respiration refers to the process by which the body obtains the oxygen necessary for cellular respiration and releases the carbon dioxide waste out to the atmosphere.

13.3  Breathing: Review Questions and Answers

1. Define breathing. Breathing, or ventilation, is the two-step process of drawing air into the lungs (inhaling) and letting air out of the lungs (exhaling).
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3. Give examples of activities in which breathing is consciously controlled. Answers may vary. Sample answer: Breathing is consciously controlled in swimming, speech training, singing, playing many musical instruments, and yoga.
4. Explain how unconscious breathing is controlled. Unconscious breathing is controlled by respiratory centres in the medulla and pons of the brainstem. These centres monitor and respond to variations in blood pH by either increasing or decreasing the rate of breathing as needed to return the pH level to the normal range.
5. Young children sometimes threaten to hold their breath until they get something they want. Why is this an idle threat? This is an idle threat because when they try to hold their breath, they will soon have an irrepressible urge to breathe.
6. Why is nasal breathing generally considered superior to mouth breathing? Nasal breathing is generally considered to be superior to mouth breathing because it does a better job of filtering, warming, and moistening incoming air. It also results in slower emptying of the lungs, which allows more oxygen to be extracted from the air.
7. Give one example of a situation that would cause blood pH to rise excessively. Explain why this occurs. Answers will vary. Sample answer: During an asthma attack, involuntary hyperventilation can occur. This causes the loss of too much carbon dioxide from the body due to the rapid rate of breathing. Carbon dioxide decreases blood pH, so the loss of too much carbon dioxide will cause blood pH to rise excessively.

13.4  Gas Exchange: Review Questions and Answers

1. What is gas exchange? Gas exchange is the biological process through which gases are transferred across cell membranes to either enter or leave the blood.
2. Summarize the flow of blood into and out of the lungs for gas exchange. The pulmonary artery carries deoxygenated blood from the heart to the lungs, where it travels through pulmonary capillaries, picking up oxygen and releasing carbon dioxide. The oxygenated blood then leaves the lungs through pulmonary veins, which carry it to the heart to be pumped to cells throughout the body.
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4. Describe the mechanism by which gas exchange takes place.  Gas exchange takes place by diffusion across cell membranes. Gas molecules naturally move down a concentration gradient from an area of higher concentration to an area of lower concentration. This is a passive process that requires no energy.
5. Identify the two main factors upon which gas exchange by diffusion depends. Gas exchange by diffusion depends on the large surface area provided by the hundreds of millions of alveoli in the lungs. It also depends on a steep concentration gradient for oxygen and carbon dioxide. This gradient is maintained by continuous blood flow and constant breathing.
6. If the concentration of oxygen were higher inside of a cell than outside of it, which way would the oxygen flow? Explain your answer. The oxygen would flow out of the cell, because gases diffuse from an area of higher concentration to an area of lower concentration across a cell membrane.
7. Why is it important that the walls of the alveoli are only one cell thick? Answers may vary. Sample answer: The walls of the alveoli being only one cell thick makes gas exchange much easier and more efficient because the gases only have to pass across a thin membrane to get to and from the bloodstream.
8. There are so many alveoli because a large surface area is needed for the diffusion necessary for gas exchange.

13.5  Disorders of the Respiratory System: Review Questions and Answers

1. Self-marking
2. How can asthma attacks be prevented? How can symptoms of asthma attacks be controlled? Ways to prevent asthma attacks include taking long-term control medications such as corticosteroids and avoiding things that trigger asthma attacks. Symptoms can be controlled by the use of bronchodilators.
3. How can pneumonia be prevented? How is it treated? Pneumonia can often be prevented with vaccines. Treatment of pneumonia depends on its cause. In cases of bacterial pneumonia, it generally includes prescription antibiotics. Treatment may also include hospitalization and supplemental oxygen.
4. 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? Primary lung cancer is a malignant tumor that originates in lung tissue. Secondary lung cancer is a malignant tumor in the lung that originates elsewhere in the body and spreads to the lung. Lung cancer is the most common cause of cancer-related death in men and the second most common cause in women. Lung cancer is so deadly in part because it is generally diagnosed too late to be cured. Lung cancer typically is treated with surgery, chemotherapy, and/or radiation therapy.
5. What is the difference between how COPD and pneumonia affect the alveoli? COPD involves the breakdown of the walls of the alveoli, reducing their number and making them less elastic. Pneumonia involves fluid build up within the alveoli.

13.6  Smoking and Health: Review Questions and Answers

1. Create a pamphlet aimed at informing teenagers about the dangers of smoking.  Include information about numbers of deaths associated with smoking, life expectancy of smokers, and long term healthy effects of smoking and exposure to second-hand smoke.  Include a section on the chemicals present in tobacco smoke and e-cigarettes and some of the adverse affects associated with these chemicals.
2. What smoking-related factors determine how smoking affects a smoker’s health? The detrimental health effects of smoking depend on the number of years that a person smokes and how much the person smokes.
3. What are the two sources of secondhand cigarette smoke? How does exposure to secondhand smoke affect non-smokers? The two sources of secondhand cigarette smoke are smoke that comes directly from burning tobacco and smoke that comes from the lungs of smokers when they exhale. Exposure to secondhand smoke affects non-smokers in much the same way as smokers are affected by smoking. For example, non-smokers exposed to secondhand smoke have as much as a 30 per cent increase in their risk of lung cancer and heart disease.
4. Why is it so difficult for smokers to quit the habit? How is their health likely to be affected by quitting? It is so difficult for smokers to quit the habit because tobacco smoke contains nicotine, which is a highly addictive psychoactive drug. After quitting, a former smoker’s risks of smoking-related diseases and death soon start to fall.
5. Why does smoking cause cancer? List five types of cancer that are significantly more likely in smokers than non-smokers. Smoking causes cancer because tobacco smoke contains dozens of chemicals that have been proven to be carcinogens. Many of these chemicals bind to DNA in a smoker’s cells and may either kill the cells or cause mutations. If the mutations inhibit programmed cell death, the cells can survive to become cancer cells. Answers may vary. Sample answer: Five types of cancer that are significantly more likely in smokers than non-smokers are cancers of the lung, kidney, larynx, mouth, and throat.
6. Explain how smoking causes COPD. Chemicals such as carbon monoxide and cyanide in tobacco smoke reduce the elasticity of alveoli, leading to COPD. The carcinogen in tobacco smoke called acrolein contributes to the chronic inflammation that is also present in COPD. COPD is almost completely preventable by not smoking and by avoiding exposure to secondhand smoke.
7. Do you think e-cigarettes can be addictive? Explain your reasoning. Answers may vary. Sample answer: I think e-cigarettes can be addictive because they contain nicotine, which is a highly addictive drug.

13.7  Case Study Conclusion and Chapter Summary: Review Questions and Answers

1. Self-marking
2. Describe the relationship between the bronchi, secondary bronchi, tertiary bronchi, and bronchioles. The bronchi are the two tubes of the airway that branch off from the trachea. The secondary bronchi branch off from the bronchi, the tertiary bronchi branch off from the secondary bronchi, and the bronchioles branch off from the tertiary bronchi. These passages get increasingly smaller as they branch off.
3. Deoxygenated and oxygenated blood both travel to the lungs. Describe what happens to each there Deoxygenated blood picks up oxygen in the lungs via gas exchange and then transports it to the heart and out to the body’s cells. Oxygenated blood is used by the cells of the lungs to carry out aerobic cellular respiration to provide energy for its functions.
4. Explain the difference between ventilation and gas exchange. Ventilation is also called breathing. It is the physical process of moving air to and from the lungs. Gas exchange refers to the biochemical process in which oxygen diffuses out of the air and into the blood while carbon dioxide and other waste gases diffuse out of the blood and into the air.
5. Which way do oxygen and carbon dioxide flow during gas exchange in the lungs, and why? Which way do oxygen and carbon dioxide flow during gas exchange between the blood and the body’s cells, and why? In the lungs, oxygen flows from the air inside the alveoli into the blood and carbon dioxide flows from the blood to the air inside the alveoli. This is because the oxygen concentration is higher in the air inside the alveoli and the carbon dioxide concentration is higher in the blood, and gases naturally diffuse from an area of higher concentration to an area of lower concentration. Oxygen flows from the blood to the body’s cells, and carbon dioxide flows from the body’s cells into the blood. This is because the oxygen concentration is higher in the blood and the carbon dioxide concentration is higher in the body’s cells, and gases naturally diffuse from an area of higher concentration to an area of lower concentration.
6. Why does the body require oxygen, and why does it emit carbon dioxide as a waste product? The body’s cells use oxygen and produce carbon dioxide as waste in the process called aerobic cellular respiration. This process provides energy needed for the body’s functions by “burning” glucose.
7. What do coughing and sneezing have in common? Answers may vary. Sample answer: Coughing and sneezing are involuntary responses that occur when the nerves in the airways or nasal passages are irritated. They are forceful responses that expel mucus and debris out of the respiratory system to keep the airways clear and to keep harmful particles out.
8. COPD can cause too much carbon dioxide in the blood. Answer the following questions about this:
   1. How does COPD cause there to be too much carbon dioxide in the blood? Answers may vary. Sample answer: COPD hampers gas exchange because the walls of the alveoli are damaged. Therefore, oxygen intake and carbon dioxide removal are impaired, which can lead to a build up of carbon dioxide in the blood.
   2. What does this do to the blood pH? Too much carbon dioxide lowers blood pH.
   3. How does the body respond to this change in blood pH? Answers may vary. Sample answer: The respiratory centres in the brain detect the drop in pH and cause the body to respond by increasing the rate of breathing.
9. What are three different types of things that can enter the respiratory system and cause illness or injury? Describe the negative health effects of each in your answer. Answers will vary. Sample answer: Foreign objects such as food can get lodged in the respiratory system and cause choking. Pathogens such as bacteria and viruses can enter the respiratory system and cause infectious diseases such as a cold, flu, or pneumonia. Carcinogenic chemicals, such as those found in tobacco smoke, can enter the respiratory system and cause cancer.
10. Where are the respiratory centres of the brain located? What is the main function of the respiratory centres of the brain? The brainstem, specifically the medulla oblongata and the pons. The main function of the respiratory centres of the brain is to regulate the rate of breathing.
11. Smoking increases the risk of getting influenza, commonly known as the flu. Explain why this could lead to a greater risk of pneumonia. Pneumonia often develops as a secondary infection after an upper respiratory infection such as the flu. Therefore, a higher risk of getting the flu also raises the risk of getting pneumonia.
12. If a person has a gene that caused them to get asthma, could changes to their environment (such as more frequent cleaning) help their asthma? Why or why not? Answers may vary. Sample answer: Even if a person has asthma due to their genetics, asthma attacks can be triggered by substances in the environment such as pet dander, dust mites, and mold. Therefore, more frequent cleaning may help lessen the frequency or severity of their asthma attacks.
13. Explain why nasal breathing generally stops particles from entering the body at an earlier stage than mouth breathing does. Answers may vary. Sample answer: The nasal passages are lined with hairs that more effectively trap particles when you inhale, as compared to the mouth.