What is Functional Residual Capacity (FRC)?

Functional Residual Capacity (FRC) is a respiratory physiology parameter that represents the volume of air present in the lungs at the end of passive expiration. It is the amount of air that remains in the lungs after a normal tidal breath is exhaled. FRC is important because it helps balance the forces that tend to collapse the lungs (elastic recoil) and those that tend to expand the chest wall (outward recoil). It plays a crucial role in maintaining efficient gas exchange in the lungs and is often used to assess respiratory disorders.