What is the Functional Residual Capacity (FRC)?

What is the Functional Residual Capacity (FRC)?

• A. Tidal volume
• B. Vital capacity
• C. Inspiratory capacity
• D. Functional Residual Capacity (FRC)

Answer: (D)

Functional Residual Capacity is the amount of air left in the lungs after a normal, passive exhalation. It equals the sum of expiratory reserve volume and residual volume, serving as a resting lung volume that keeps airways open and provides a reservoir of gas between breaths for continuous gas exchange. This is distinct from tidal volume, which is the air moved in or out during a typical breath; from vital capacity, which is the total air exhaled after a maximal inhalation; and from inspiratory capacity, which is the maximum air you can inhale after a normal exhale.

Functional Residual Capacity is the amount of air left in the lungs after a normal, passive exhalation. It equals the sum of expiratory reserve volume and residual volume, serving as a resting lung volume that keeps airways open and provides a reservoir of gas between breaths for continuous gas exchange. This is distinct from tidal volume, which is the air moved in or out during a typical breath; from vital capacity, which is the total air exhaled after a maximal inhalation; and from inspiratory capacity, which is the maximum air you can inhale after a normal exhale.