Respiratory Definitions

inspiratory capacity

equals the tidal volume plus the inspiratory reserve volume; amount of air a person can breathe in, beginning at the normal expiratory level and distending the lungs to the maximum amount

functional residual capacity

expiratory reserve volume plus the residual volume; amount of air that remains in the lungs at the end of normal expiration

vital capacity

inspiratory reserve volume plus the tidal volume plus the expiratory resreve volume; maximum amount of air a person can expel from the lungs after first filling the lungs to their maximum extent and then expiring to the maximum extent

expiratory reserve volume

maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration

inspiratory reserve volume

maximum extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with full force

total lung capacity

maximum volume to which the lungs can be expanded with the greatest possible effort; equal to the vital capacity and the residual volume

tidal volume

volume of air inspired or expired with each breath

residual volume

volume of air remaining in the lungs after the most forceful expiratinon