bisc307 exam final _sp. 05%2C byerly_

# bisc307 exam final _sp. 05%2C byerly_ - Final Exam BISC...

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NAME ____________________________________ Page 2 of 9 1. (6 points) Give typical values for P CO2 and P O2 in (a) alveolar air, and (b) freshly inhaled air in the nasal passage. (c) How can these numbers be used to calculate the respiratory exchange ratio (R) for the individual? 2. (4 points) How does congestive heart failure affect lung function? Briefly explain the mechanism of this effect. 3. (6 points) Suggest (in the table below) reasonable values for the lung pressure (P L ) and pleural pressure (P Pl ) during the given three conditions of breathing. Pressures are measured relative to atmospheric pressure; P B = 0. P L (mm Hg) P PL (mm Hg) All respiratory muscles relaxed. 0 -3.7 During expiration from above condition. +1 -1 After maximum inspiration. No air flow. 0 -7 a) In alveolar air, P O2 = 102 mH; P CO2 = 40 mH. b) In fresh air, P O2 = 150 mH; P CO2 = 0 mH. c) R = (CO 2 produced) / (O 2 consumed) = (40 – 0) / (150 – 102) = 0.8 Congestive heart failure produces pulmonary edema, which decreases the ability of the lung to exchange gases. The reduced ability of the left ventricle to pump blood causes the pressure in the pulmonary vein (and capillaries) to increase. This increases capillary filtration, causing edema.
NAME ____________________________________ Page 3 of 9 4. (6 points) Why are smaller alveoli more prone to collapse (than larger alveoli) in premature infants? How is this problem solved in the lungs of a healthy infant? 5. (8 points) The ventilation/perfusion ratio (V A / Q) is 0.2 for a region of the lung. Estimate values for the partial pressure of O 2 and CO 2 for the alveolar air in this region. What changes will each of the abnormal partial pressures produce in local bronchioles or arterioles? 6.

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## This note was uploaded on 05/03/2010 for the course BISC 307L taught by Professor Herrera during the Spring '08 term at USC.

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bisc307 exam final _sp. 05%2C byerly_ - Final Exam BISC...

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