What is the normal tidal volume in milliliters?

• A. 250 mL
• B. 500 mL
• C. 750 mL
• D. 1000 mL

Answer: (B)

Tidal volume refers to the amount of air that is inhaled or exhaled during normal, resting breathing. In healthy adults, the typical tidal volume is around 500 milliliters per breath. This value is essential in understanding various physiological conditions, as it serves as a baseline for assessing pulmonary function.

A tidal volume of 500 mL allows for efficient gas exchange in the alveoli, ensuring adequate oxygen delivery to the bloodstream and removal of carbon dioxide. This volume is important for maintaining adequate ventilation and meeting the metabolic needs of the body at rest.

The other values provided are either too low or too high compared to the normal tidal volume for adults. A tidal volume of 250 mL would be more characteristic of children or infants, while values like 750 mL and 1000 mL exceed the typical volume for normal adult respiration, indicating possible hyperventilation or increased work of breathing. Thus, 500 mL accurately represents the normal tidal volume in a healthy adult.