Alveolar ventilation refers to the volume of air that participates in gas exchange?

• A. Alveolar ventilation
• B. Inspiratory capacity
• C. Tidal volume
• D. Residual volume

Answer: (A)

Alveolar ventilation is the portion of inhaled air that actually reaches the alveoli and participates in gas exchange. On a single breath, not all of the tidal volume is usable for gas exchange because some air stays in the conducting airways—the dead space. So the air that reaches the alveoli per breath is roughly tidal volume minus dead space, and the alveolar ventilation rate is this amount times the breathing rate (VA = (VT − VD) × f).

That’s why this option is the best fit: it describes air involved in gas exchange, unlike inspiratory capacity (the maximum you can inhale after normal exhalation), tidal volume (the total air moved per breath, including dead space air), or residual volume (air remaining after maximal exhalation, not the air actively participating in gas exchange).