Chapter 12 Egan's Testbanks

Chapter 12 Egan's Testbanks Gaseous diffusion 1 and 3 only 6. Under what conditions will the alveolar PACO2 rise above normal? a. If both metabolic rate and ventilation increase (e.g., through exercise) b. If carbon dioxide production decreases relative to VA c. If VA decreases relative to carbon dioxide production d. When the patient is febrile If VA decreases relative to carbon dioxide production 7. A 70-kg male patient has a CO2 of 200 ml/min and a VA of 9 L/min. From this information, what can you infer? a. The patient's carbon dioxide production is abnormally low. b. The patient's A is abnormally low. c. The patient will have a lower than normal PACO2. d. The patient will have a higher than normal PACO2. The patient will have a lower than normal PACO2. 8. What is the primary determinant of the PAO2? a. Body's CO2 b. Metabolic rate of the body tissues c. PaO2 d. PO2 in the inspired gas PO2 in the inspired gas 9. The PAO2 depends on which of the following factors? 1. Ambient (atmospheric) pressure 2. Fractional concentration of inspired O2 3. Level of VA 4. Types of fuels burned (fat, protein, and carbohydrate) a. 1, 2, and 3 only b. 1 and 2 only c. 3 only d. 1, 2, 3, and 4 1, 2, 3, and 4 10. Calculate the approximate PAO2 given the following conditions (assume R = 0.8): FiO2 = .40, PB = 770 mm Hg, PACO2 = 31 mm Hg a. 100 mm Hg b. 135 mm Hg c. 250 mm Hg d. 723 mm Hg 250 mm Hg 11. A healthy person breathing 100% O2 at sea level would have PAO2 of approximately what level? a. 149 mm Hg b. 670 mm Hg c. 713 mm Hg d. 760 mm Hg 670 mm Hg 12. Which of the following best represents the partial pressures of all gases in the normally ventilated and perfused alveolus when breathing room air at sea level? a. PO2 = 40 mm Hg; PCO2 = 100 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg b. PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg c. PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 713 mm Hg; PH2O = 47 mm Hg d. PO2 = 149 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg b. PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg 13. In a person breathing room air (and with all else being normal), if the alveolar PCO2 rises from 40 to 70 mm Hg, what would you expect? a. PAO2 to fall by approximately 30 mm Hg b. PAO2 to fall by approximately 40 mm Hg c. PAO2 to rise by approximately30 mm Hg d. PAO2 to rise by approximately 40 mm Hg PAO2 to fall by approximately 30 mm Hg 14. Assuming a constant FiO2 and carbon dioxide production, which of the following statements is correct? a. An increased PACO2 will result in and increased PAO2. b. Increased FIO2 blows off carbon dioxide. c. Increases in alveolar ventilation (VA) decrease the PACO2 and increase the PAO2. d. The PAO2 varies proportionally with the PACO2. Increases in alveolar ventilation (VA) decrease the PACO2 and increase the PAO2. 15. What is the highest PAO2 one could expect to observe in an individual breathing room air at sea level? a. 90 to 100 mm Hg b. 110 to 120 mm Hg c. 640 to 670 mm Hg d. 710 to 760 mm Hg 110 to 120 mm Hg 16. Which of the following conditions must exist for gas to move between the alveolus and pulmonary capillary? a. Adequate alveolar ventilation (VA) b. Difference in partial pressures (pressure gradient) c. Normal central nervous system (CNS) control mechanism d. Sufficient amount of blood hemoglobin (Hb) Difference in partial pressures (pressure gradient) 17. Which of the following "layers" must be traversed by gases moving across the alveolar-capillary membrane? 1. Alveolar epithelial membrane 2. Capillary endothelial membrane 3. Interstitial space 4. Transbronchial radial tethering mechanisms a. 1, 2, and 3 only b. 1, 2, and 4 only c. 2 and 3 only d. 1, 2, 3, and 4 1, 2, and 3 only 18. When is the rate of gaseous diffusion across a biological membrane decreased? a. The diffusion distance is small. b. The gas diffusion constant increases. c. The partial pressure gradient is low. d. The surface area is large. The partial pressure gradient is low. 19. Which of the following values corresponds most closely to the normal PO2 and PCO2 in the mixed venous blood returning to the lungs from the right side of the heart? a. PO2 = 40 mm Hg; PCO2 = 46 mm Hg b. PO2 = 40 mm Hg; PCO2 = 100 mm Hg c. PO2 = 100 mm Hg; PCO2 = 40 mm Hg d. PO2 = 100 mm Hg; PCO2 = 46 mm Hg PO2 = 40 mm Hg; PCO2 = 46 mm Hg 20. Which of the following gases would diffuse fastest across the alveolar-capillary membrane? a. Air b. Carbon dioxide c. O2 d. Nitrogen Carbon dioxide 21. Carbon dioxide diffuses across the alveolar-capillary membrane approximately how many times faster than O2? a. 10 b. 20 c. 30 d. 40 20 22. The time available for diffusion in the lung is mainly a function of which of the following? a. Functional residual capacity (FRC) b. Inspired O2 concentration c. Level of VA d. Rate of pulmonary blood flow Rate of pulmonary blood flow 23. What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of O2 to occur across the alveolar-capillary membrane? a. 0.15 sec b. 0.25 sec c. 0.35 sec d. 0.45 sec 0.25 sec 24. What is the primary factor that maintains the pressure gradient that drives O2 from the capillaries into the interstitial spaces and into the cells? a. Bohr effect on the RBC b. Cellular consumption of O2 c. Haldane effect on the RBC d. Increased carbon dioxide in blood decreasing Hb affinity for O2 Cellular consumption of O2 25. In order to assess the events occurring at the tissue level, especially tissue oxygenation, what parameter would you sample and measure? a. Coronary sinus blood b. Left-sided heart blood c.