DAT Biology - Problem Drill 12: The Respiratory System Question No. 1 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 1. Which statement about the partial pressure of oxygen inside the lungs is correct? (A) The partial pressure in the lungs is higher than in the blood, and oxygen diffuses out of the lungs passively. (B) The partial pressure in the lungs is lower than in the blood, and oxygen Question #01 diffuses out of the lungs passively. (C) The partial pressure in the lungs is higher than in the blood, and the carbon dioxide partial pressure in the lungs is equal with the blood. (D) The partial pressure in the lungs is higher than in the blood, and oxygen is actively transported to an area of higher concentration. (E) None of the above A. Correct! The partial pressure in the lungs is higher than in the blood, so the oxygen diffuses out of the lungs passively. B. Incorrect! The partial pressure in the lungs is higher than in the blood. Feedback on Each Answer C. Incorrect! Choice The carbon dioxide partial pressure in the lungs is lower than in the blood. D. Incorrect! Oxygen diffuses passively into the blood and moves towards an area of lower concentration. E. Incorrect! There is one correct answer above. Oxygen and carbon dioxide exchange passively between the pulmonary capillaries and the alveoli. These gases move along their partial pressure gradients, i.e.- from high to low. The partial pressure of oxygen is higher in the lungs. Therefore, oxygen moves along its pressure gradient from the lung into the blood. The partial Solution pressure of carbon dioxide is higher in the blood. Therefore, carbon dioxide moves along its pressure gradient from blood into the lungs to be exhaled. The correct answer is (A). RapidLearningCenter.com © Rapid Learning Inc. All Rights Reserved Question No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 2. The blood entering the pulmonary capillaries has _____ (prior to gas exchange)? (A) Higher partial pressure of oxygen than when it leaves the lungs. (B) Lower partial pressure of oxygen than when it leaves the lungs. Question #02 (C) Lower partial pressure of carbon dioxide than when it leaves the lungs. (D) The same partial pressure of oxygen when it leaves the lungs. (E) The same partial pressure of carbon dioxide when it leaves the lungs. A. Incorrect! The blood has lower partial pressure of oxygen than when it leaves the lungs. B. Correct! The blood has lower partial pressure of oxygen than when it leaves the lungs. C. Incorrect! Feedback on The blood has higher partial pressure of carbon dioxide than when it leaves the Each Answer lungs. Choice D. Incorrect! Initially, the partial pressure of oxygen in the blood is low and after gas exchange it increases. This causes the partial pressure of oxygen to be higher when it leaves the lungs. E. Incorrect! The blood has lower partial pressure of oxygen than when it leaves the lungs. Initially, the partial pressure of oxygen is low, but after gas exchange it increases. This causes the partial pressure of oxygen to be higher when it leaves the lungs. When the blood enters the pulmonary capillaries PO = 40 mmHg and PCO = 45 Solution 2 2 mmHg. After gas exchange, PO2 = 100 mmHg and PCO2 = 40 mmHg. The correct answer is (B). RapidLearningCenter.com © Rapid Learning Inc. All Rights Reserved Question No. 3 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 3. What are two methods the respiratory system uses to protect the body from foreign particles and pathogens? (A) Traps foreign particles and pathogens in the mucous of the lungs and stores it in the lungs. (B) Traps foreign bodies and pathogens in the mucous of the lungs and moves it towards the mouth to be swallowed and removed/destroyed by the Question #03 gastrointestinal tract. (C) Alveolar macrophages phagocitize foreign bodies and pathogens and release them back into the alveoli for removal during exhalation. (D) Alveolar macrophages phagocitize foreign bodies and pathogens that only leave the lungs in the ascending layer of mucous. (E) None of the above A. Incorrect! The trapped foreign particles and pathogens are not stored in the lungs. B. Correct! The respiratory system traps foreign bodies and pathogens in the mucous of the lungs and moves it towards the mouth to be swallowed and removed/destroyed by the gastrointestinal tract. Feedback on C. Incorrect! Each Answer Alveolar macrophages phagocitize foreign bodies and pathogens, but remove them Choice from the lungs. D. Incorrect! Alveolar macrophages phagocitize foreign bodies and pathogens that either leave the lungs in the ascending layer of mucous or through the alveolar lymphatic system. E. Incorrect! There is one correct answer above. The respiratory system protects the human body from foreign particles and pathogens by (a) trapping foreign bodies and pathogens in the mucous of the lungs and moving the trapped particles towards the mouth to be swallowed and removed/destroyed by the gastrointestinal tract, or (b) through alveolar Solution macrophages that phagocitize foreign bodies and pathogens that then either leave the lungs in the ascending layer of mucous or through the alveolar lymphatic system. The correct answer is (B). RapidLearningCenter.com © Rapid Learning Inc. All Rights Reserved Question No. 4 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 4. Which of the following statements about the respiratory system’s involvement in thermoregulation is correct? (A) The inspired air is heated in the lungs to the internal body temperature of 37ºC and humidified to 100%. (B) The inspired air is heated in the lungs to the internal body temperature of Question #04 30ºC and is humidified to 100%. (C) During exhalation the expired air is cooled to 20ºC. (D) The temperature of air in the lungs is similar to the temperature of the air in the external environment, throughout the breathing cycle. (E) None of the above A. Correct! The inspired air is heated in the lungs to the internal body temperature of 37ºC and is humidified to 100%. B. Incorrect! The inspired air is heated in the lungs to the internal body temperature of 37ºC. Feedback on Each Answer C. Incorrect! Choice Expired air is about 30ºC. D. Incorrect! Inspired air is heated or cooled to the internal body temperature. E. Incorrect! There is one correct answer above. During inhalation, room temperature air is brought into the respiratory system and heated or cooled to internal body temperature (37ºC, 100% humidity). Air in the lungs, below the trachea, is ~37ºC and 100% humidified. During exhalation, expired gas is 100% humidified and about 30ºC. Therefore, if you are breathing in Solution a room where the external environment is 20ºC and you are exhaling air from the lungs that is about 30ºC, there is a net heat loss to the environment. The correct answer is (A). RapidLearningCenter.com © Rapid Learning Inc. All Rights Reserved Question No. 5 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 5. Which of the following statements about respiratory mechanics is correct? (A) During quiet breathing the diaphragm contracts and returns to its pre- inhalation position through active processes. (B) Breathing is an active and passive process under involuntary control only. Question #05 (C) During quiet breathing the diaphragm actively contracts and returns to its pre-inhalation position passively. (D) During exhalation the chest wall expands and the diaphragm contracts. (E) During quiet breathing the diaphragm remains at the same position. A. Incorrect! During quiet breathing the diaphragm contracts and returns to its pre-inhalation position passively. B. Incorrect! Breathing is under voluntary and involuntary control. C. Correct! Feedback on During quiet breathing the diaphragm actively contracts and returns to its pre- Each Answer inhalation position passively. Choice D. Incorrect! During inhalation the chest wall expands and the diaphragm contracts. E. Incorrect! No, it does not. During quiet breathing the diaphragm actively contracts and returns to its pre-inhalation position passively. Breathing is an active process of muscle activity, under voluntary and involuntary control. During quiet breathing, the diaphragm is the major muscle involved in the breathing cycle. During inhalation the chest wall expands and the diaphragm contracts. During exhalation the diaphragm relaxes to its pre-inhalation position Solution passively. The correct answer is (C). RapidLearningCenter.com © Rapid Learning Inc. All Rights Reserved Question No. 6 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 6. Which of the statements best describes the pressure inside of the lungs during the breathing cycle? (A) Less than the atmospheric pressure at the end of exhalation, just before the beginning of inhalation. (B) When the diaphragm actively contracts at the beginning of inhalation, the internal lung volume decreases and the internal pressure inside the lung increases.