(a) Inspiratory Reserve volume (IRV): Additional volume of air, a person can inspire by a forcible inspiration.
(b) Expiratory Reserve volume (ERV): Additional volume of air, a person can expire by a forcible expiration.
(c) Total lung capacity: Total volume of air accommodated in the lungs at the end of a forced inspiration. This includes RV, ERV, TV and IRV.
(d) Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration.
(e) Functional residual capacity (FRC): Volume of air that will remain in the lungs after a normal expiration. This includes ERV + RV.
