What term describes the normal volume of air displaced between normal inhalation and exhalation without extra effort?

The term that describes the normal volume of air displaced between normal inhalation and exhalation without extra effort is tidal volume. Tidal volume reflects the amount of air that is inhaled or exhaled during regular, restful breathing. This volume is typically around 500 mL in a healthy adult at rest and is essential for understanding respiratory mechanics. It's a primary measure of lung function, often assessed in various clinical and exercise settings to evaluate a person's respiratory health.

Vital capacity refers to the maximum amount of air that can be exhaled after a maximum inhalation, which is a larger measure that includes tidal volume but also incorporates reserve volumes. Inspiratory reserve volume and expiratory reserve volume are specific to the additional air that can be inhaled or exhaled beyond the tidal volume and are not indicative of the normal breathing cycle occurring at rest. Therefore, tidal volume is the appropriate term for the described scenario.