Functional residual capacity (FRC)

Definition

Functional Residual Capacity (FRC) is the volume of air remaining in the lungs after a normal, passive exhalation. It represents the equilibrium point where the forces of lung recoil and chest wall expansion are balanced.

5 Must Know Facts For Your Next Test

1. FRC is typically about 2400 mL in an average adult.
2. It includes the expiratory reserve volume (ERV) and residual volume (RV).
3. FRC plays a crucial role in maintaining consistent gas exchange even between breaths.
4. A reduction in FRC can lead to hypoxemia due to inadequate oxygen reserves.
5. Factors like body posture, obesity, and lung diseases can significantly alter FRC.

Review Questions

• What components make up Functional Residual Capacity?
• Why is FRC important for gas exchange in the lungs?
• How can body posture affect Functional Residual Capacity?

Related terms

Expiratory Reserve Volume (ERV): The additional amount of air that can be forcibly exhaled after normal exhalation.

Residual Volume (RV): The amount of air remaining in the lungs after a maximal exhalation.

Total Lung Capacity (TLC): The maximum volume of air that the lungs can hold, including all lung volumes.