Chapter 13 PDF

MULTIPLE CHOICE 1. The entire sequence of events involved in the exchange of O2 and CO2 between the body cells and the surrounding environment is known as a. internal respiration b. external respiration c. ventilation d. breathing e. ventilation and breathing...

MULTIPLE CHOICE 1. The entire sequence of events involved in the exchange of O2 and CO2 between the body cells and the surrounding environment is known as a. internal respiration b. external respiration c. ventilation d. breathing e. ventilation and breathing B 2. The respiratory quotient is a. the rate at which gases diffuse across the alveolar capillary membrane b. respiratory rate times tidal volume c. the ratio of O2 consumed to CO2 produced d. the ratio of CO2 produced to O2 consumed e. equal to 1.0 on a typical American diet D 3. Which activity below is not a respiratory event? a. Carbon dioxide is exchanged in the alveoli. b. Cells produce nitrogen by their metabolism. c. Gas exchange between tissues and the blood. d. Oxygen is exchanged in the alveoli. e. Pulmonary ventilation. B 4. Type I alveolar cells a. form the wall of the alveoli b. secrete pulmonary surfactant c. contract during expiration to force air out of the alveoli d. have characteristics a and c e. have all of the above characteristics A 5. In addition to gas exchange, the respiratory system plays a key role in a. enhancing venous return b. water and temperature balance c. body defense d. enhancing venous return and body defense e. all of the above E 6. Which of the following structures serves as a common passageway for both the respiratory and digestive systems? a. nose b. pharynx c. trachea d. bronchi e. esophagus B 395  7. Which of the following is not a function of the respiratory system? a. transports O2 to the tissues b. contributes to maintenance of normal acid-base balance c. provides a route for heat and water elimination d. enables speech, singing, and other vocalization e. removes, modifies, activates, or inactivates various materials passing through the pulmonary circulation A 8. During which of the following would the intrapleural pressure be greater than atmospheric pressure? a. forced inspiration b. passive expiration c. passive inspiration d. pneumothorax e. None of the above E 9. The intrapulmonary pressure a. is the pressure within the air sacs of the lung b. always equilibrates with atmospheric pressure c. is always less than intrapleural pressure d. is both a and b e. is both a and c ED 10. The lungs are held against the thoracic wall due to a. the negative intrapleural pressure b. the positive intrapulmonary pressure c. cohesiveness of the pleural fluids d. all of the above e. only a and c D 11. A transmural pressure gradient exists across the lung wall because the ____ pressure is less than the ____ pressure. a. intrapleural; intra-alveolar b. intra-alveolar; intrapleural c. intrapleural; atmospheric d. atmospheric; intra-alveolar e. atmospheric; intrapleural A 12. The inspiratory muscles include the a. diaphragm and internal intercostal muscles b. diaphragm and external intercostal muscles c. diaphragm and abdominal muscles d. internal and external intercostal muscles e. intercostal and abdominal muscles B 396 13. Under normal conditions, when _______ pressure becomes greater than _______ pressure, air will flow out of the lungs. a. intra-alveolar, atmospheric b. intra-alveolar, intrapleural c. intrapleural, intra-alveolar d. intrapleural, atmospheric e. atmospheric, intra-alveolar A 14. Which statement is incorrect? a. Alveoli are the site of gas exchange in the lungs. b. Pores of Kohn allow air to flow between adjacent bronchioles. c. Alveolar Type II cells secrete pulmonary surfactant. d. Alveoli are very thin and are surrounded by a network of capillaries so that air and blood are separated by a very thin barrier. e. The alveoli are thin-walled, inflatable, grape-like sacs at the end of the bronchioles. B 15. At the end of a normal expiration, when outward air flow has ceased, a. Intra-alveolar pressure is less than atmospheric pressure. b. Intra-alveolar pressure is greater than atmospheric pressure. c. Intra-alveolar pressure is equal to atmospheric pressure. d. Intrapleural pressure is greater than atmospheric pressure. e. Intrapleural pressure is greater than intra-alveolar pressure. C 16. Inspiratory events occur because a. the air pressure in the alveoli is greater than that of the atmosphere b. the air pressure in the alveoli is less than that of the atmosphere c. the volume of the thoracic cavity increases d. of conditions a and b e. of conditions b and c E 17. Which of the following is the last step that produces an inspiration? a. The atmospheric pressure becomes lower than the intrapleural pressure. b. The diaphragm contracts. c. The intercostal muscles contract. d. The intra-alveolar pressure becomes lower than the atmospheric pressure. e. The intrapleural pressure becomes positive. D 397 18. Airway resistance a. is normally the primary factor determining the amount of flow into/out of the lungs b. decreases when the diameter of the airways becomes reduced c. when elevated, requires an increased pressure gradient between the lungs and atmosphere through vigorous respiratory efforts to move even normal volumes of air into and out of the lungs d. is lower in people with asthma e. decreases when lung compliance increases C 19. During inspiration, a. intra-alveolar pressure falls below atmospheric pressure. b. the diaphragm contracts. c. the internal intercostal muscles contract. d. conditions a and b exist e. conditions a, b, and c exist D 20. When the diaphragm contracts, a. the volume of the thoracic cavity increases b. lung volume increases as the lungs are forced to expand c. the intra-alveolar pressure increases d. both a and b occur e. a, b, and c occur D 21. During forceful expiration, a. accessory expiratory muscles contract b. internal intercostals contract c. abdominal muscles contract d. ribs are brought closer together e. all of the above occur E 22. Normal expiration is brought on by a. contraction of the external intercostals b. contraction of the internal intercostals c. contraction of the diaphragm d. elastic recoil of inspiratory muscles e. elastic recoil of expiratory muscles D 23. Which of the following makes breathing more difficult? a. Increased pulmonary compliance b. Increased airway resistance c. Decreased elastic recoil d. both a and c e. both b and c E 398 24. Which of the following is/are innervated by the phrenic nerve? a. abdominal muscles b. diaphragm c. external intercostal muscles d. internal intercostal muscles e. accessory inspiratory muscles B 25. Which of the following does not occur during expiration when a person is breathing quietly? a. The size of the thoracic cavity is reduced. b. The intra-alveolar pressure becomes greater than atmospheric pressure. c. Air flows out of the lungs. d. The expiratory muscles contract. e. Intrapleural pressure remains less than intra-alveolar pressure. D 26. Which of the following does not bring about increased airway resistance? a. asthma b. epinephrine c. slow-reactive substance of anaphylaxis d. emphysema e. excess mucus production B 27. Bronchodilation of the air passages involves the ____ of their smooth muscle and the ____ of their radius. a. decrease; decrease b. decrease; increase c. increase; decrease d. increase; increase e. None of the above B 28. Which factor would result in bronchoconstriction? a. sympathetic stimulation b. parasympathetic stimulation c. epinephrine secretion d. increased carbon dioxide concentration e. None of the above B 29. Which of the following is incorrect if blood flow to an area of the lungs is reduced while airflow remains normal? a. The concentration of CO2 in this area decreases. b. The change in CO2 concentration causes smooth muscles of the local airways to relax. c. The change in CO2 concentration leads to increased resistance of local airways. d. The change in O2 concentration leads to dilation of local blood vessels. B 399 30. When the level of blood flow is not ideally matched with the amount of airflow in a localized area of lung tissue, a. autoregulatory mechanisms are invoked b. the autonomic nervous system couples the events more ideally c. and if airflow is low and blood flow too high, arteriolar vasoconstriction occurs d. both a and b occur e. both a and c occur E 31. Which of the following promotes elastic recoil of the lungs? a. Elastic fibers in the lung b. Surface tension of the fluid lining the alveoli c. Pulmonary surfactant d. Both a and b e. All of the above D 32. Which of the following statements concerning pulmonary surfactant is incorrect? a. It is secreted by Type II alveolar cells. b. It is deficient in newborn respiratory distress syndrome. c. It promotes elastic recoil of the lungs. d. It reduces the cohesive force between water molecules. e. It reduces surface tension. C 33. Pulmonary surfactant a. is secreted by Type II alveolar cells b. decreases surface tension of the fluid lining the alveoli c. resists elastic recoil of the lungs d. is a combination of lipids and proteins e. has all of the above characteristics E 34. Without pulmonary surfactant, a. small alveoli would tend to collapse b. larger alveoli would tend to empty into smaller alveoli c. all alveoli would be easier to inflate d. the surface tension in the alveoli would be reduced e. inspiration would be easier A 35. The work of breathing normally requires about 3% of total energy expenditure; this increases under all of the following situations except when a. elastic recoil decreases b. resistance increases c. the partial pressure of oxygen increases in the air d. ventilation increases e. compliance decreases C 400 36. The minimum volume of air that remains in the lungs after a maximal expiration is termed the a. tidal volume b. functional residual capacity c. residual volume d. vital capacity e. None of the above C 37. The residual volume is a. important in helping prevent lung collapse b. the normal volume of air inhaled c. the normal volume of air exhaled d. the maximum volume of air that can be inspired e. the minimum volume of air that can be inspired A 38. The vital capacity is a. the volume normally entering or leaving the lungs during a single breath b. the difference in volume between maximum inspiration and maximum exhalation c. the maximum volume the lungs can hold d. the minimum volume the lungs can hold e. none of these B 39. Which type of chronic obstructive pulmonary disease is characterized by a breakdown of alveolar walls and collapse of the smaller airways? a. asthma b. chronic bronchitis c. emphysema d. All of the above e. Only b and c C 40. Which of the following would not be expected for a patient suffering from obstructive lung disease? a. normal total lung capacity b. increased functional residual capacity c. decreased residual volume d. decreased FEV1 e. None of the above would be affected C 41. Compliance refers specifically to the a. effort required to stretch the lungs b. elasticity of the lung tissue c. energy requirements for an inspiration d. surface area of the alveoli e. volume of air moved per breathing cycle A 401 42. Which of the following forces does not contribute to keeping the alveoli open? a. alveolar surface tension b. transmural pressure gradient c. pulmonary surfactant d. Movement of air between alveoli through pores of Kohn e. None of the above contribute to keeping the alveoli open. A 43. Intrapleural pressure exceeds airway pressure a. during normal quiet breathing b. during maximal forced expiration c. in response to a pneumothorax d. during maximal forced expiration and in response to a pneumothorax e. in all of the above situations B 44. A person who has a tidal volume of 400 ml/breath, a respiratory rate of 14 breaths/minute, and an anatomic dead space volume of 120 ml will have a pulmonary ventilation rate of a. 3000 ml/minute b. 3920 ml/minute c. 4260 ml/minute d. 5600 ml/minute e. 6240 ml/minute D 45. Which condition would result in the lowest alveolar ventilation rate? a. quiet breathing b. a normal respiratory rate and normal tidal volume c. a low respiratory rate and high tidal volume d. a high respiratory rate and very low tidal volume e. a low respiratory rate and very low tidal volume E 46. If the pulmonary ventilation rate is 3200 ml/minute with a tidal volume of 400, the respiratory rate is ____ breaths per minute. a. 6 b. 8 c. 14 d. 16 e. 20 B 47. A person who has a tidal volume of 400 ml, a respiratory rate of 14, and an anatomic dead space volume of 150 ml will have an alveolar ventilation rate of a. 3,500 ml/minute b. 3,920 ml/minute c. 4,260 ml/minute d. 5,600 ml/minute e. 6,240 ml/minute A 402 48. Which factor would reduce the alveolar ventilation rate the most? a. increased alveolar dead space b. decreased alveolar dead space c. increased respiratory rate d. increased tidal volume e. quiet breathing A 49. If 20% of the air is composed of O2, the partial pressure of oxygen at sea level where atmospheric pressure is 760 mm Hg is a. 20 mm Hg b. 760 mm Hg c. 70 mm Hg d. 350 mm Hg e. 152 mm Hg E 50. If 20% of the air is composed of O2, the partial pressure of oxygen at an altitude of 20,000 feet where atmospheric pressure is 350 mm Hg is a. 20 mm Hg b. 760 mm Hg c. 70 mm Hg d. 350 mm Hg e. 152 mm Hg C 51. in the blood is a. the pressure exerted by the amount of oxygen dissolved in the blood b. the most important factor determining the percent saturation of hemoglobin c. normal in carbon monoxide poisoning d. only a and b e. a, b, and c E 52. The partial pressure of oxygen a. in the atmospheric air averages 79 percent of total atmospheric pressure b. in blood is the most important factor that determines percent O2 saturation of Hb c. in arterial blood decreases when Hb preferentially combines with CO rather than O2 d. is both b and c e. is none of the above B 403 53. If the alveolar is 100 mm Hg, the blood leaving the pulmonary capillaries in a normal person will have a of a. 40 mm Hg b. 46 mm Hg c. 100 mm Hg d. 760 mm Hg e. none of these C 54. Which of the following would decrease diffusion of a gas across the alveolar/pulmonary capillary membrane? a. An increase in thickness of the membrane b. An increase in surface area of the membrane c. An increase in the partial pressure gradient d. a and c only e. a, b, and c A 55. Systemic venous is ____ alveolar , and systemic venous is ____ alveolar. a. greater than, greater than b. greater than, less than c. less than, greater than d. less than, less than e. equal to, equal to C 56. The partial pressure of oxygen in the pulmonary veins is a. about 40 mmHg b. equivalent to alveolar partial pressure c. dramatically different than pulmonary arteries partial pressure d. equivalent to the partial pressure of oxygen in the arteriolar ends of systemic capillaries e. all of the above E 57. Which factor would reduce the amount of oxygen transfer across the respiratory membrane? a. a higher partial pressure of oxygen in the atmosphere b. an abnormally high partial pressure of carbon dioxide in the atmosphere c. a reduced partial pressure of carbon dioxide in the atmosphere d. a low pulmonary capillary partial pressure of oxygen e. None of the above B 58. Hemoglobin a. plays a critical role in determining the total amount of O2 that is exchanged in the lungs because it removes O2 and keeps the low so that net diffusion continues b. combines only with O2 c. is found in erythrocytes d. does both a and c e. does none of the above D 404 59. The percent of hemoglobin saturation decreases as a. increases b. increases c. H+ decreases d. body temperature decreases e. blood pH decreases B 60. All of the following would result in lower oxygen saturation of hemoglobin except a. an increase in b. an increase in temperature c. an increase in d. a decrease in pH e. an increase in DPG A 61. The atmospheric is approximately a. 25 mm Hg b. 120 mm Hg c. 160 mm Hg d. 220 mm Hg e. the same as for nitrogen C 62. Hemoglobin has the greatest affinity for a. carbon dioxide b. oxygen c. carbon monoxide d. nitrogen e. sulfur dioxide C 63. Approximately what percentage of oxygen is transported in the blood dissolved in free form? a. 1.5 b. 15 c. 60 d. 72 e. 100 A 405 64. The plateau portion of the O2-Hb curve a. is in the blood- range that exists at pulmonary capillaries b. means that Hb becomes nearly saturated in the lungs unless pulmonary capillary falls below 60 mm Hg c. is in the blood- range that exists at the systemic capillaries d. is both a and b e. is both b and c D 65. Select the incorrect statement about hemoglobin. a. It combines with oxygen at the lungs. b. It contains iron. c. It forms an irreversible association with oxygen. d. It is located inside the red blood cell. e. Its globin portion is a polypeptide. C 66. Identify the correct statement(s). a. The presence of Hb keeps blood low and favors O2 movement into the blood. b. Hb can combine with O2, CO2, H+, and CO. c. Hb unloads more O2 in the presence of increased tissue acidity. d. Hb buffers against changes in pH due to respiratory carbonic acid. e. All of the statements are true. E 67. The amount of oxygen unloaded from Hb at the tissue level increases when a. in the tissue increases b. the concentration of DPG in the red blood cells increases c. the concentration of CO2 in the red blood cells decreases d. a and b occur e. a and c occur B 68. Hemoglobin a. combines preferentially with O2 over any other substance b. is known as carboxyhemoglobin when combined with carbon dioxide c. plays a critical role in determining the amount of O2 exchanged between alveoli and blood d. has characteristics a and c e. has all of the above characteristics C 69. Approximately what percent of carbon dioxide is transported in the blood dissolved in dissolved form? a. 1.5 b. 10 c. 35 d. 60 e. 100 B 406 70. Carbon dioxide is transported in the blood in all the following ways except a. bicarbonate ion b. carbonic acid c. directly dissolved d. bound to heme e. bound to globin DE 71. What is the primary form in which CO2 is transported in the blood? a. physically dissolved b. bound to hemoglobin c. bound to plasma protein d. as bicarbonate e. as carbonic anhydrase D 72. Carbonic anhydrase a. is found in the red blood cells b. catalyzes the formation of carbonic acid from carbonic dioxide and water c. catalyzes the formation of oxyhemoglobin from oxygen and reduced hemoglobin d. has characteristics a and b e. has characteristics b and c D 73. The chloride shift in red blood cells a. causes the development of an electrical gradient b. occurs in response to bicarbonate movement into the plasma c. causes a decrease in blood pH d. involves the exchange of H+ for Cl- ions on hemoglobin molecules e. involves the exchange of HCO3- for Cl- ions on hemoglobin B 74. 2,3-diphosphoglycerate a. is produced within red blood cells b. production is inhibited by HbO2 c. concentration gradually increases when Hb in the arterial blood is chronically undersaturated d. can bind with Hb e. has all of the above characteristics E 75. Which condition exists at high altitudes? a. histotoxic hypoxia b. hypoxic hypoxia c. anemic hypoxia d. hypocapnia e. None of the above B 407 76. Hypercapnia a. refers to excess CO2 in the arterial blood b. occurs when CO2 is blown off to the atmosphere at a rate faster than it is being produced by the tissues c. may be caused by hypoventilation d. would likely result in a higher percent saturation of oxygen on Hb e. would tend to raise the blood’s pH A 77. The brain region that provides output to the respiratory muscles is located in the a. pons b. medulla c. cerebral cortex d. cerebellum e. hypothalamus B 78. Identify the correct statement(s). a. The DRG consists of both inspiratory neurons and expiratory neurons. b. The neurons of the DRG remain inactive during normal quiet breathing. c. The DRG is called into play by the VRG as when demands for ventilation are increased. d. All of the above are correct. e. None of the above are correct. E 79. The stretch receptors for the Hering-Breuer reflex are located in the a. diaphragm b. elastic tissue of the lungs c. medulla d. smooth muscle of the airways e. trachea D 80. Pacemaker activity that establishes the rhythmicity of breathing resides in the a. lung tissue b. respiratory muscles c. dorsal respiratory group d. phrenic nerve e. cerebrum C 81. The inspiratory neurons a. activate the phrenic nerve, bringing about contraction of the diaphragm b. are stimulated by stretch receptors c. are inhibited by the DRG when the DRG is stimulated by the apneustic area d. have characteristics a and c e. have characteristics b and c A 408 82. The apneustic center a. is located in the medulla b. stimulates the inspiratory neurons c. inhibits inspiratory activity d. stimulates the pneumotaxic area e. performs c and d B 83. Expiratory neurons a. are found in both the DRG and VRG b. send impulses to the expiratory muscles during normal quiet breathing c. are stimulated by the phrenic nerve d. are stimulated by the apneustic area e. are inactive during quiet breathing E 84. The primary regulator of the magnitude of ventilation in normal circumstances is the a. H+ concentration of the brain extracellular fluid monitored by central chemoreceptors b. of the arterial blood monitored by central chemoreceptors c. of the arterial blood monitored by peripheral chemoreceptors d. of arterial blood monitored by central chemoreceptors e. of arterial blood monitored by peripheral chemoreceptors A 85. Which statement about peripheral chemoreceptors is incorrect? a. They are stimulated whenever the arterial falls below normal. b. They are stimulated by a rise in arterial. c. They are stimulated by an increase in arterial H+. d. They are located in the carotid arteries and in the aortic arch. e. When stimulated, they reflexively increase ventilation. A 86. The receptors that are stimulated by a large drop in the blood level are located in a. the respiratory center of the brain b. carotid and aortic bodies c. tissue capillaries d. both b and c e. all of the above B 409 87. The factor in the arterial blood that has the largest effect on increasing the rate of respiration is a. an increase in the hydrogen ion concentration in the kidneys b. an increase in the hydrogen ion concentration in the arterial blood c. any decrease in the partial pressure of carbon dioxide d. any decrease in oxygen's partial pressure e. the detection of CO2 by central chemoreceptors B 88. Ventilation is increased the most by a. increases in arterial b. decreases in arterial c. increases in arterial d. decreases in arterial e. none of the above A 89. At high altitudes, the alveolar a. is higher than normal b. is lower than normal c. is higher than normal d. and are higher than normal e. is lower than normal and is higher than normal B 90. Red blood cells in which of the following would likely contain the highest concentration of chloride ions in their cytoplasm? a. left atrium b. pulmonary vein c. aorta d. pulmonary artery e. arteriolar end of a systemic capillary D 91. Which of the following decreases Hb’s affinity for oxygen? a. increased blood pH b. low partial pressure for CO2 c. high BPG d. high partial pressure for O2 e. decreased concentration of H+ C 410 92. Choose the structure that likely contains red blood cells with the most carbaminohemoglobin. a. systemic arterioles b. venule end of a pulmonary capillary c. left atrium d. pulmonary vein e. venule end of a systemic capillary E 93. Identify the factor(s) that would increase Hb’s affinity for carbon dioxide in a red blood cell. a. Lowering the concentration of carbon dioxide in the cell b. Lowering the concentration of H+ in the cell c. Raising the pH in the cell d. Increasing the amount of reduced hemoglobin in the cell e. Decreasing the amount of DPG in the cell D 94. HbH would be in a higher percentage within a red blood cell in which of the following? a. pulmonary artery b. left atrium c. systemic arteriole d. venule end of a pulmonary capillary e. pulmonary vein A 95. Choose the pairing that has the least related items: a. Haldane, Hb affinity for carbon dioxide b. VRG, inspiration and expiration c. Apneustic area, inspiration d. Pneumotaxic area, expiration e. Hering-Breuer, Hb affinity for oxygen E 411 TRUE/FALSE 1. The respiratory system is the only system involved with the exchange of gas between the cells of an organism and the external environment. F 2. Gases are transported during external respiration by active transport mechanisms. F 3. Respiration is accomplished entirely by the respiratory system. F 4. Exhaled air passes from the larynx through the trachea. F 5. Both the respiratory system and the circulatory system are involved in the process of respiration. T 6. The respiratory system provides a route for water and heat elimination. T 7. The respiratory airways filter, warm, and humidify incoming air. T 8. The intrapleural cavity is located inside the lungs. F 9. All respiratory airways are held open by cartilaginous rings. F 10. The alveoli are encircled by capillaries. T 11. Air flow through the smaller bronchioles can be adjusted by varying the contractile activity of the smooth muscle within their walls. T 12. Pores of Kohn permit air flow between adjacent alveoli, a process known as collateral ventilation. T 412 13. The bronchioles are rigid, non-muscular airways, encircled by a series of cartilaginous rings. F 14. The "negative" intrapleural pressure, when compared to atmospheric pressure, maintains lung inflation. T 15. The pleural cavity normally is not in direct communication with the atmosphere. T 16. At the end of inspiration and at the end of expiration, intra-alveolar pressure is always equal to atmospheric pressure. T 17. At the end of inspiration and at the end of expiration, intrapleural pressure is always equal to atmospheric pressure. F 18. For inspiration to occur, the intra-alveolar pressure must be lower than the atmospheric pressure. T 19. Under normal conditions, intrapleural pressure is always less than atmospheric pressure. T 20. Intrapleural pressure normally does not equilibrate with the intra-alveolar pressure. T 21. The abdominal muscles are expiratory muscles. T 22. The internal intercostal muscles are inspiratory muscles because they lift the ribs upward and outward to enlarge the thoracic cavity. F (Above: they are not inspiratory, they are expiratory!) 23. At a constant temperature, the pressure that a gas exerts depends on the volume that it occupies. T 24. In the breathing cycle, the atmospheric pressure normally does not change. T 413 25. The quantity of air that will flow into and out of the lungs depends solely on the radius of the respiratory airways. F 26. Inspiration is always an active process. T 27. Expiration is always a passive process. F 28. Stimulation of the sympathetic nervous system and epinephrine release lead to an increase in airway resistance. F 29. Elastic recoil refers to the tendency of the chest wall to expand. F 30. Pulmonary surfactant increases alveolar surface tension but does not affect lung expansion. F 31. Pulmonary surfactant is secreted by Type II alveolar cells. T 32. Pulmonary surfactant reduces the work of breathing and increases lung stability by increasing alveolar surface tension. F 33. Newborn respiratory distress syndrome is caused by an excess of pulmonary surfactant. F 34. If there is a deficient supply of pulmonary surfactant, the lungs become more compliant. F 35. A highly compliant lung is easier to stretch than a less compliant one. T 36. A pneumothorax allows intrapleural pressure to equilibrate with atmospheric pressure. T 414 37. Pneumothorax develops from the accumulation of fluid in the alveoli. F 38. Emphysema can be brought on by recurrent episodes of asthma and/or chronic bronchitis. T 39. An increase in airway resistance and an increase in alveolar surface tension both increase the work of breathing. T 40. In the absence of pulmonary surfactant, smaller alveoli display a larger inward-directed pressure than do larger alveoli. T 41. According to Laplace's law, the magnitude of the inward-directed collapsing pressure of a spherical bubble is directly proportional to both the surface tension and the radius of the bubble. F 42. Pulmonary surfactant decreases surface tension to a greater degree in large alveoli than in small alveoli. F 43. Patients suffering from chronic obstructive pulmonary disease generally have more trouble exhaling than inhaling. T 44. Boyle's law states that the pressure exerted by a gas varies directly with the volume of the gas. F 45. To produce a normal tidal volume, the expiratory muscles must be stimulated. F 46. The residual volume is the amount of air remaining in the lungs at the end of a normal expiration. FT 47. Deep breaths usually result in the greatest alveolar ventilation rates. T 48. If a person is breathing rapidly, it is safe to assume that he or she is getting adequate ventilation. F 415 49. The skeletal muscles for breathing are located in the walls of the lungs. F 50. The 500 ml of air that is inspired is the same 500 ml of air that enters the alveoli during a single breath. F 51. If the tidal volume is 500 ml and the anatomic dead space volume is 150 ml, only 350 ml of air enters the alveoli during inspiration. F (Above: 350 mL is the correct number. But, all 500 mL enters the alveoli. Only 350 mL actually undergoes successful gas exchange.) 52. Slow, deep breathing is more effective for increasing alveolar ventilation than is rapid, shallow breathing. T 53. O2 moves from regions of low partial pressure to regions of high partial pressure. F 54. During external respiration, the is greater in the alveoli than in the blood of the pulmonary capillaries. T 55. During external respiration, the is greater in the blood of the pulmonary capillaries than in the alveoli. T 56. The partial pressure of a gas in blood depends on the amount that is physically dissolved and not on the total content of the gas present in the blood. T 57. Alveolar partial pressures do not fluctuate to any extent between inspiration and expiration. T 58. The tidal volume is the sum of the vital capacity, expiratory reserve volume, and inspiratory reserve volume. F 59. The quantity of O2 that will diffuse between the alveolar air and pulmonary blood depends solely on the partial pressure gradients that exist between the alveoli and blood. F 416 60. Systemic arterial is greater than tissue. T 61. Systemic arterial is less than tissue. T 62. A molecule of nitrogen exerts more pressure than a molecule of oxygen because nitrogen is a larger molecule. F 63. The partial pressure of nitrogen in the atmosphere is greater than the partial pressure of oxygen in the atmosphere. T 64. Alveolar is higher following inspiration than following expiration. F (Above: not “following inspiration”, PO2 is higher during inspiration) 65. The most important factor that determines the extent to which hemoglobin is saturated with oxygen is the blood. T 66. Increased acidity at the tissue cells stimulates increased dissociation of oxyhemoglobin. T 67. O2 is much more soluble in blood than CO2 is. F (Above: it’s the opposite, CO2 is more soluble) 68. At the systemic capillaries, the is in the range of the steep portion of the O2-Hb curve. T 69. Carbonic anhydrase catalyzes the formation of the oxyhemoglobin. F 70. During hyperventilation, arterial levels decrease because CO2 is blown off more rapidly than it is being produced in the tissues. T 417 71. In the plateau region of the Hb-O2 curve, a large decrease in results in a small decrease in Hb saturation, whereas in the steep portion of the curve, a small decrease in results in a large decrease in percent Hb saturation. T 72. The combination of Hb and CO2 is known as carbaminohemoglobin. T 73. The peripheral chemoreceptors are not activated during carbon monoxide poisoning despite the fact that the total O2 content in the blood can become lethally low. T 74. Administering O2 to patients with severe chronic lung disease will not depress their drive to breathe. F 75. Arterial remains normal or may even increase slightly during exercise despite the fact that O2 consumption by the tissues is greatly increased. T 76. Respiration is reflexively inhibited by alkalosis caused by a reduction in concentration of non-carbon- dioxide-generated H+. T 77. The respiratory center is located in the cerebral cortex. F 78. The most important factor controlling respiration is the of arterial blood. F 79. O2 levels are much more closely regulated than CO2 levels in the arterial blood. F 80. A slight decrease in arterial below normal is a more potent stimulus toward increasing respiration than is a slight increase in above normal. F 81. When inspiratory neurons stop firing, the expiratory muscles will contract. F 418 82. The inspiratory and expiratory neurons both display pacemaker activity. F 83. The pneumotaxic and apneustic centers are located in the cerebellum. F 84. Receptors in the CNS that detect changes in arterial are actually sensitive to the H+ concentration of the brain extracellular fluid. T 85. The primary factor believed to be responsible for stimulating the profound and abrupt increase in ventilation during exercise is increased arterial. F 86. Red blood cells in the pulmonary vein would contain a higher concentration of chloride ions than red blood cells in the pulmonary artery. F 87. Well-ventilated alveoli usually receive more blood flow than more poorly-ventilated alveoli. T 88. Hemoglobin’s affinity for carbon dioxide is higher in systemic capillaries than in pulmonary capillaries. T 89. More bicarbonate ions diffuse out of red blood cells in exchange for chloride while those cells are in the systemic capillaries compared to when they are in the pulmonary capillaries. T 90. According to Fick’s Law, gas diffuses faster through a thin respiratory membrane than through a thicker respiratory membrane. T 419 COMPLETION Complete each of the following statements.. The _______________ serves as the largest respiratory airway of the respiratory system, and the ______________ are the gas-exchanging portion. trachea, alveoli 2. Pulmonary ventilation is another name for the mechanical act of ____________________. breathing 3. The respiratory quotient is the ratio of ____________________ to ____________________. CO2 produced, O2 consumed 4. The exchange of O2 and CO2 between the external environment and lungs is known as ____________________. external respiration 5. The vocal folds are found in the ____________________, which is found at the top of the ____________________, or windpipe. larynx, trachea 6. The ____________________ serves as a common passageway for both the respiratory and digestive systems. pharynx 7. The alveolar wall is ____________________ (how many?) cell layer(s) thick, and the wall of the pulmonary capillaries surrounding an alveolus is ____________________ (how many?) cell layer(s) thick. one, one 8. ____________________ is the inflammation of the pleural sac. Pleurisy 420  9. ____________________ refers to air flow between adjacent alveoli through the pores of Kohn. Collateral ventilation 10. The most profound changes in thoracic volume can be accomplished by contraction of the ____________________. diaphragm 11. The atmospheric, or ____________________, pressure is the pressure exerted by the weight of the air in the atmosphere. barometric 12. According to ____________________ law, at any constant temperature, the pressure of a gas varies inversely with the volume of the gas. Boyle's 13. ____________________ refers to air in the pleural cavity. Pneumothorax 14. A(n) ____________________ pressure across the chest wall influences lung movements. transmural 15. The ____________________ nerve supplies the diaphragm. phrenic 16. Contraction of the ____________________ intercostal muscles elevates the ribs. external 17. The ____________________ is a double-walled, closed sac that separates each lung from the thoracic wall and other surrounding structures. pleural sac 18. ____________________ is a respiratory disease characterized by collapse of the smaller airways and a breakdown of alveolar walls. Emphysema 421 19. When relaxing, the diaphragm moves ____________________(up or down?), resulting in a(n) (increase or decrease?) in thoracic pressure. up, increase 20. The maximum volume of air that can be moved in and out of the lungs in a single breath is known as the ____________________. vital capacity 21. The volume occupied by the conducting airways is known as the ____________________. anatomic dead space 22. As the resistance of the air passages increases, the airflow through them _______________ (increases or decreases?) if the pressure gradient remains constant. decreases 23. The primary factor that determines the percent Hb saturation is the ____________________. 24. ____________________ ions shift into the red blood cells to maintain electric neutrality when HCO3- moves out of the cells down its concentration gradient. Chloride 25. Pulmonary surfactant contributes to lung stability by _______________ (increasing or decreasing?) surface tension. decreasing 26. The ____________________ effect refers to the reduced affinity of Hb for O2 in the presence of increased CO2 and H+. Bohr 27. The ____________________ effect refers to the increased affinity of Hb for CO2 and H+ after O2 unloading. Haldane 422 28. The ____________________ is the maximum volume of air that can be inspired at the end of a normal quiet expiration. inspiratory capacity 29. ____________________ refers to a ventilation rate that exceeds the metabolic needs of the body. Hyperventilation 30. The primary respiratory control center that provides output to the respiratory muscles is located in the ____________________ (specific part of brain). medulla 31. An increase of ____________________ ions in the arterial blood changes the respiratory rate by increasing it. hydrogen 32. The apneustic and pneumotaxic centers are located in the ____________________ (specific part of brain). pons 33. A drop in the oxygen levels in arterial blood __________________ (increases or decreases?) central chemoreceptor activity. depresses 34. The DRG consists mostly of __________________ (inspiratory or expiratory) neurons. inspiratory 35. The VRG consists of ____________________ and ____________________ neurons. inspiratory, expiratory 36. The partial pressure of _______ in the arteries is normally the most important input in regulating the magnitude of ventilation under resting conditions. carbon dioxide 423 37. The peripheral chemoreceptors are located in the ____________________ and ____________________ bodies. carotid, aortic 38. ____________________ is the transient cessation of breathing. Apnea 39. The subjective sensation of not getting enough air is known as ____________________. dyspnea 40. If the concentration of carbon dioxide at sea level (760 mm Hg) is 0.04 of 1.0%, the partial pressure of this gas is ____________________ mm of Hg. 0.304 41. If the vital capacity of a person is 4800 ml, while the TV 500 ml and the ERV 900 ml, the IRV is ____________________ ml. 3400 42. According to _______ law, making the respiratory membrane thicker by coating it with excess mucus would cause ______ (increase or decrease?) the exchange rate of gases through that membrane. Fick’s, decrease Application 43. ______(Hypo or Hyper?)ventilation would ______ (increase or decrease?) the level of carbon dioxide in the blood, and this would decrease the activity of the carotid bodies. Hyper, decrease 44. Increased ventilation that matches an increased metabolic demand, such as the increase need for O2 delivery and CO2 elimination during exercise, is termed _______. hyperpnea 424 45. _______ (Contraction or Relaxation?) of the diaphragm ______ (increases or decreases?) the volume of the thoracic cavity, which, in turn causes intra-alveolar pressure to increase. Relaxation, decreases 46. Intrapleural pressure would suddenly _______ (increase or decrease?) if a person experiences a pneumothorax just as he/she completes normal expiration. increases Application 47. When a person is experiencing an asthma attack, his/her FEV1 would be ________(higher or lower?) than normal. lower 48. A local ______ (increase or decrease?) in CO2 within alveoli cause constriction of the airways leading to those alveoli. decrease 49. A local _______ (increase or decrease?) in oxygen partial pressure within pulmonary arterioles causes vasoconstriction within those arterioles. increase 50. A _______ (high or low?) level of CO2 in local airways causes dilation of those airways, and a ______ (high or low?) level of O2 in pulmonary arterioles causes dilation of those arterioles. high, high 425 MATCHING Indicate which type of hypoxia would be present in each of the circumstances listed below by writing the appropriate letter in the blank using the following answer code. a. anemic hypoxia 1. Cyanide poisoning b. circulatory hypoxia 2. High altitude c. histotoxic hypoxia 3. Carbon monoxide poisoning d. hypoxic hypoxia 4. Emphysema 5. Hemoglobin deficiency 6. Congestive heart failure 1. C 2. D 3. A 4. D 5. A 6. B Indicate which lung volume or capacity is being described in the column below by filling in the appropriate letter in the blank. a. vital capacity 7. Respiratory rate x (tidal volume - dead space volume) H b. respiratory rate 8. Maximum volume of air that the lungs can hold c. FEV1 9. The volume of air entering or leaving the lungs in a single d. tidal volume breath during quiet breathing A e. residual volume 10. The minimum volume of air remaining in the lungs after f. total lung capacity maximal expiration E g. functional residual 11. The extra volume of air that can be maximally inspired over capacity and above the tidal volume J h. alveolar ventilation 12. Amount of air breathed in and out in one minute I i. pulmonary ventilation 13. Maximum volume of air that can be moved in and out j. inspiratory reserve during a single breath volume k. expiratory reserve 14. Volume of air that can be expired during the first second of volume expiration in a vital-capacity determination l. inspiratory capacity 15. The maximum volume of air that can be inspired at the end m. anatomic dead space of a normal expiration volume 16. Inspiratory reserve volume + tidal volume + expiratory reserve volume A 17. Vital capacity + residual volume 18. Volume of air in the respiratory airways M HFDE JIAC LAFM KIGHB 19. The extra volume of air that can be actively expired by contraction of expiratory muscles beyond that normally expired 20. Respiratory rate x tidal volume 21. Volume of air in the lungs at the end of a normal passive expiration 22. Amount of air available for exchange of gases with the blood per minute 23. Breaths/minute 426  Indicate the effect the following changes would have on the rate of gas transfer using the following answer code. a. Increases the rate of gas 24. Effect of pulmonary fibrosis on O2 and CO2 exchange within the transfer lungs B b. Decreases the rate of gas 25. Effect of emphysema on O2 and CO2 exchange within the lungs B transfer 26. Effect of a fall in atmospheric on O2 exchange within the c. Has no effect on the rate of gas transfer lungs B 27. Effect on O2 exchange in the lungs of replacing part of the nitrogen with helium so that the inspired air consists of 60% N, 19% He, and 21% O2 C 28. Effect of increased metabolism of a cell on O2 and CO2 exchange between the cell and blood A 29. Effect of tissue edema on O2 and CO2 exchange between the surrounding cells and blood B 30. Effect of reduced systemic venous on O2 exchange within the lungs A 24. B 25. B 26. B 27. C 28. A 29. B 30. A Indicate which chemical factor is responsible for the effect described. a. arterial between 60 to 100 mm Hg 31. Stimulates peripheral chemoreceptors and is important in the b. arterial less than 60 regulation of acid-base balance E 32. Directly depresses the central chemoreceptors B mm Hg 33. Weakly stimulates the peripheral chemoreceptors C/D c. arterial increased 34. Stimulates peripheral chemoreceptors as an emergency above normal mechanism B d. brain ECF H+ increased 35. Directly stimulates the central chemoreceptors and represents the above normal dominant control of ventilation C/D e. arterial H+ increased 36. Has no effect on the peripheral chemoreceptors A above normal 31. E 32. B 33. C 34. B 35. D 36. A 395 ART-BASED QUESTIONS Use this figure to answer the corresponding questions.. Which number identifies the most specific structure that contains type II cells? 8 2. The structure labeled 3 is the right ________. bronchus 3. Number ____ identifies the vessel containing the highest , and it is called the ____________________. 9, pulmonary artery 4. Number ____ on the figure at the left identifies the structure most affected in asthma, and it is called a(n) ____________________. 4, bronchiole 396  Use this figure to answer the corresponding questions. 5. Which number(s) relate(s) only to an amount of air inhaled? 2, 3 6. Number ____ identifies the ____________________, which is the maximum amount of air that can be exhaled after maximum inhalation. 7, vital capacity 7. Number ____ identifies the ____________________, which is the minimum amount of air left in the lungs after maximum exhalation. 5, residual volume 8. Number 3 identifies the ____________________, which is the sum of the ____________________, identified as number ____, and ____________________, identified as number ____. inspiratory capacity, inspiratory reserve volume, 2, tidal volume, 1 397 ESSAY 1. In addition to providing for gas exchange, list five other functions of the respiratory system. (Any five of the following) (1) Provides route for water loss and heat elimination (2) Heats and moistens incoming air so that gas exchange is more efficient (3) Functions as respiratory pump to enhance the return of blood to the heart (4) Helps maintain normal acid-base balance by altering the amount of CO2 and H+ in the blood (5) Enables speech, singing, and other vocalizations (6) Defends against inhaled foreign matter (7) Removes, modifies, activates, or inactivates various materials passing through the pulmonary circulation 2. Describe the mechanics of ventilation as it relates to Boyles' Law. Include the following in your answer: intra-alveolar pressure, intrapleural pressure, atmospheric pressure, inhalation, and exhalation. Boyles' Law states that the pressure within a chamber is inversely correlated to the size of the chamber. The thorax is a closed chamber and it encloses the lungs. When muscles cause the thorax to increase in volume, the intrapleural pressure (around the lungs) decreases, causing the lungs to expand and decrease the intra-alveolar pressure (inside the lungs). When the intra-alveolar pressure drops below atmospheric pressure, air rushes into the lungs (inhalation occurs). When the thorax recoils or is compressed, its volume decreases and its pressure increases, which in turn increases the intra-alveolar pressure. When intra-alveolar pressure exceeds atmospheric pressure, air rushes out of the lungs (exhalation occurs). 3. What factors influence the amount of gas exchange occurring at the respiratory membrane? Include the following in your answer: , , mucus, and surfactant. The amount of gas exchange in the lungs depends on the concentration gradients for O2 and CO2 in the alveoli and the blood within capillaries around the alveoli. Since is higher in the alveoli than in the blood, O2 diffuses into the blood; and since is higher in the blood than in the alveoli, CO2 diffuses into the alveoli. Accumulation of mucus in the alveoli increases the distance that these gases must travel between the blood and alveoli, thus decreasing the rate of gas exchange. Surfactant helps keep alveolar walls from sticking together; thus, the alveoli inflate easily and this allows gas exchange to occur more efficiently. 398 4. Describe how temperature, blood pH, BPG, and affect hemoglobin's percent saturation for O2. Include the Bohr effect in your answer. As temperature, BPG, and increase around Hb, there is a decrease in Hb's affinity (binding strength) for O2. Under these conditions, Hb's percent saturation with O2 decreases. Hb's decreased affinity for O2 when is high is called the Bohr effect. When blood pH decreases (becomes more acidic), more H+ ions bind with Hb and decrease Hb's affinity for O2; this is also part of the Bohr effect. 5. Describe the location and importance of the following to various patterns of breathing: DRG, VRG, pre-Bötzinger complex, apneustic area, and pneumotaxic area. The DRG, VRG, pre-Bötzinger complex, apneustic area, and pneumotaxic areas are located within the medulla oblongata of the brain. The DRG consists of inspiratory neurons that stimulate inhalation muscle for restful inhalation. When these neurons stop firing, exhalation occurs. The VRG consists of inspiratory and expiratory neurons that stimulate breathing muscles for forced inhalation and forced exhalation. The pre-Bötzinger complex is thought to be responsible for stimulating the DRG and making restful, rhythmic breathing possible. The apneustic area stimulates inspiratory neurons in the DRG to prolong inhalation. The pneumotaxic area inhibits the DRG and overrides the effect of the apneustic area to limit the length of inhalation events during restful breathing. 399