What is alveolar ventilation?

• A. Volume of air that reaches the alveoli
• B. Volume of air that doesn't reach the alveoli
• C. Volume of air exhaled
• D. Total volume of lung capacity

Answer: (A)

Alveolar ventilation refers to the amount of air that actually reaches the alveoli and is available for gas exchange in the lungs. This is crucial for effective respiration because only the air that reaches the alveoli can participate in the exchange of oxygen and carbon dioxide with the blood.

In contrast, some air that is inhaled does not reach the alveoli due to the anatomical dead space, which consists of the airways where gas exchange does not occur. Therefore, while total ventilation is important, it is the air that specifically enters the alveolar sacs that is significant for efficient oxygenation of the blood. Understanding this distinction is fundamental in pathophysiology, particularly when assessing conditions that might affect ventilation and gas exchange in respiratory disorders.