Anatomy and Physiology II Practice Test

What term describes the greatest amount of air that one can breathe out in a single expiration?

1. tidal volume

2. vital capacity

3. reserve volume

4. dead space

The correct answer is: vital capacity

The term that describes the greatest amount of air that one can breathe out in a single expiration is vital capacity. Vital capacity is a measure of lung function and represents the maximum volume of air that can be exhaled after a deep inhalation. It is calculated by adding together the tidal volume, the inspiratory reserve volume, and the expiratory reserve volume. This measurement is important in assessing the strength and capacity of the respiratory system, making it a key indicator of pulmonary health. While tidal volume refers to the amount of air inhaled or exhaled during normal breathing, it is not the maximum effort and, therefore, does not represent the greatest amount of air expelled. Reserve volume refers to the extra amount of air that can be inhaled or exhaled beyond the normal tidal volume, but it does not account for the maximum expiration capacity. Dead space refers to the portions of the respiratory system that do not participate in gas exchange, like some airways, and is not related to the volume of air exhaled. Thus, vital capacity specifically reflects the total potential for air movement in and out of the lungs during maximal effort, making it the correct answer to this question.