ANATOMY

Detailed explanation-1: -It is the total amount of air exhaled after maximal inhalation. The value is about 4800mL and it varies according to age and body size. It is calculated by summing tidal volume, inspiratory reserve volume, and expiratory reserve volume. VC = TV+IRV+ERV.

Detailed explanation-2: -Stated differently, vital capacity is the maximum volume of gas that can be exhaled after a maximum inhalation.

Detailed explanation-3: -The inspiratory capacity (IC) is the maximal volume that can be inspired from functional residual capacity; it is equal to the sum of tidal volume and inspiratory reserve volume.

Detailed explanation-4: -The average total lung capacity of an adult human male is about 3 litres of air. Tidal breathing is normal, resting breathing; the tidal volume is the volume of air that is inhaled or exhaled in only a single such breath.

Detailed explanation-5: -The expiratory reserve volume (ERV) is the additional amount of air that can be exhaled after a normal exhalation. It is the reserve amount that can be exhaled beyond what is normal. Conversely, the inspiratory reserve volume (IRV) is the additional amount of air that can be inhaled after a normal inhalation.