Residual volume is what?

Residual volume is what?

• A. The air remaining in the lungs after a maximal exhalation
• B. The air that participates in gas exchange
• C. The air that can never be exhaled
• D. The air per breath during quiet breathing

Answer: (A)

Residual volume is the air left in the lungs after you exhale as forcefully as possible. This amount cannot be removed even with maximal effort, so a small quantity of air remains in the airways and alveoli to keep the lungs from collapsing and to allow a minimal level of gas exchange between breaths. It’s not the air you breathe in or out during normal breathing, and standard spirometry can’t measure it directly because you can’t fully empty the lungs with typical tests. This leftover air helps define total lung capacity when added to the volumes you can exhale.

Residual volume is the air left in the lungs after you exhale as forcefully as possible. This amount cannot be removed even with maximal effort, so a small quantity of air remains in the airways and alveoli to keep the lungs from collapsing and to allow a minimal level of gas exchange between breaths. It’s not the air you breathe in or out during normal breathing, and standard spirometry can’t measure it directly because you can’t fully empty the lungs with typical tests. This leftover air helps define total lung capacity when added to the volumes you can exhale.