Residual volume (RV)

Definition

Residual volume (RV) is the amount of air remaining in the lungs after a maximal exhalation. It cannot be voluntarily expelled and ensures that the lungs do not collapse.

5 Must Know Facts For Your Next Test

1. Residual volume typically ranges from 1,200 to 1,500 mL in adults.
2. It is crucial for maintaining alveolar inflation and gas exchange even between breaths.
3. RV is measured using techniques like body plethysmography or gas dilution.
4. Changes in RV can indicate respiratory conditions such as emphysema or chronic obstructive pulmonary disease (COPD).
5. RV contributes to the total lung capacity (TLC), which includes all volumes of air within the lungs.

Review Questions

• What is residual volume and why can't it be voluntarily expelled?
• How does residual volume help maintain alveolar inflation?
• Name two techniques used to measure residual volume.

Related terms

Tidal Volume (TV): The amount of air inhaled or exhaled during normal breathing.

Vital Capacity (VC): The maximum amount of air a person can expel from the lungs after a maximum inhalation.

Total Lung Capacity (TLC): The total volume of air contained in the lungs after a maximal inhalation, including residual volume.