Chapter 18 - Gas Exchange and Transport

Question 1

normal alveolar and arterial PO2

Answer 1

about 100 mm Hg

Question 2

normal alveolar and arterial PCO2

Answer 2

about 40 mm Hg

Question 3

normal venous PO2

Answer 3

40 mm Hg

Question 4

normal venous PCO2

Answer 4

46 mm Hg

Question 5

hypoxic hypoxia

Answer 5

low arterial PO2. typically caused by high altitude, alveolar hypoventilation, decreased lung diffusion capacity, abnormal ventilation-perfusion ratio

Question 6

anemic hypoxia

Answer 6

decreased total amount of O2 bound to Hgb. typical causes: blood loss, anemia, CO poisoning

Question 7

ischemic hypoxia

Answer 7

reduced blood flow. typical causes: heart failure, shock (peripheral hypoxia), thrombosis (hypoxia in a single organ)

Question 8

histotoxic hypoxia

Answer 8

failure of cells to use O2 b/c cells have been poisoned. typical causes: cyanide and other metabolic poisons

Question 9

normal arterial pH

Answer 9

7.4 (7.38-7.42)

Question 10

normal venous pH

Answer 10

7.37

Question 11

emphysema

Answer 11

destruction of alveoli means less surface area for gas exchange

Question 12

fibrotic lung disease

Answer 12

thickened alveolar membrane slows gas exchange. loss of lung compliance may decrease alveolar ventilation

Question 13

pulmonary edema

Answer 13

fluid in interstitial space increases diffusion distance. arterial PCO2 may be normal d/t higher CO2 solubility in water

Question 14

asthma

Answer 14

increased airway resistance decreases alveolar ventilation