Question

In normal lungs 

A. The rate of alveolar ventilation at rest exceeds the rate of alveolar capillary perfusion. 

B. The ventilation/perfusion (V/P) ratio exceeds 1.0 during maximal exercise. 

C. The V/P ratio is higher at the apex than at the base of the lungs when a person is standing. 

D. Oxygen transfer can be explained by passive diffusion. 

E. Dead space increases during inspiration.

Answer 1

A. False Alveolar ventilation at rest is about 4 l/min; perfusion is about 5 l/min. 

B. True In maximal exercise, alveolar ventilation may rise to about 80 l/min whereas alveolar perfusion (cardiac output) rises to about 25 l/min. 

C. True Perfusion decreases from base to apex; ventilation does also but to a lesser extent. 

D. True There is no evidence of O₂ secretion in the lungs. 

E. True The trachea and bronchi expand as the lungs expand.