What is the term for the air that remains in the lungs after maximal expiration?

The term for the air that remains in the lungs after maximal expiration is referred to as residual volume. This is an important concept in respiratory physiology because it represents the amount of air that cannot be voluntarily expelled from the lungs.

Residual volume plays a significant role in maintaining lung function and gas exchange. It ensures that the alveoli remain open and aids in preventing lung collapse (atelectasis) by ensuring a continual presence of air. Understanding residual volume is critical for interpreting lung function tests and assessing a patient’s respiratory status.

In contrast, tidal volume refers to the amount of air inhaled or exhaled during normal breathing, vital capacity is the maximum amount of air expelled after taking a deep breath, and minute volume is the total volume of air inhaled or exhaled in one minute, calculated as tidal volume multiplied by the respiratory rate. These concepts are foundational in evaluating respiratory mechanics, but they do not pertain to the air remaining in the lungs after maximum expiration.