Question

When all muscles of respiration are relaxed and alveolar pressure is zero, lung volume is equal to...

a) residual volume
b) vital capacity
c) functional residual capacity
d) tidal volume
e) total lung capacity

Answer 1

The lung volume when all muscles of respiration are relaxed and alveolar pressure is zero is equal to the functional residual capacity (FRC). This volume represents the amount of air in the lungs at the end of a normal breath.

Step-by-step explanation:

The lung volume when all muscles of respiration are relaxed and alveolar pressure is zero is equal to the functional residual capacity (FRC). The FRC is the amount of air that remains in the lungs after a tidal expiration, and it is the sum of the expiratory reserve volume and the residual volume. It represents the volume of air in the lungs at the end of a normal breath.