What is the difference between tidal volume and vital capacity?

• A. Alveoli
• B. Lungs
• C. Ventricles
• D. Bronchi

Answer: (C)

These terms describe how much air the lungs move and store during breathing. Tidal volume is the amount of air that moves in and out with each normal breath. Vital capacity is the maximum amount of air a person can exhale after a deep, full inhalation, which equals the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. In healthy adults, tidal volume is about 500 mL per breath, while vital capacity is roughly 4–5 L, though it varies with body size and fitness. These concepts pertain to the lungs, not the heart, so the best choice among the options is the lungs. Alveoli and bronchi are parts of the lungs, while ventricles are chambers of the heart.