Vital capacity of lung is ______.

IRV + ERV + TV

Vital capacity is the maximum volume of air a person can breathe in after a forced expiration or breathe out after a forced inspiration. This includes inspiratory reserve volume (IRV), tidal volume (TV) and expiratory reserve volume (ERV).

(2) IRV + ERV only does not include the tidal volume, which is also a component of vital capacity.

(3) IRV + ERV + TV + RV includes the residual volume (RV), which is the volume of air remaining in the lungs after maximum exhalation. The residual volume is not part of the vital capacity, as it cannot be exhaled.

(4) IRV + ERV + TV – RV is not the correct option. There is no need to subtract RV from IRV + ERV + TV to get the tidal
volume.