Functional residual capacity is

Functional Residual Capacity (FRC) is expiratory reserve volume + residual volume. From the picture givERV+RV) Lung Capacities The total lung capacity can be broken down into alternate capacities that help to define functioning lings. The vital capacity refers to the maximum amount of air expired from the fully inflated lung or maximum inspiratory level. The inspiratory capacity is the maximum amount of air inspired from the end-expiratory level. The functional residual capacity represents the volume of the air remaining in the lungs after expiration of a normal breath. REf: Ganong&;s Review of Medical Physiology 25th edition PGno: 628, 629