The amount of air that moves in and out of the lungs during a normal breath is called

• A. Tidal volume
• B. Residual volume
• C. Vital capacity
• D. Inspiratory reserve

Answer: (A)

During normal, quiet breathing the amount of air that moves in and out with each breath is tidal volume. This is the regular, resting breath rather than the total air the lungs can hold or the extra air you can take in with effort. Residual volume is the air left in the lungs after a full exhale and isn’t part of a normal breath; vital capacity is the maximum air you can exhale after a full inhale; inspiratory reserve is the extra air you can inhale beyond a normal inhalation. So tidal volume best describes the air exchanged in a typical breath.