Final answer:
Alveolar ventilation (VA) differs from minute ventilation (VE) as VA specifically measures air that participates in gas exchange in the alveoli, while VE includes all air moved in and out of the lungs.
Step-by-step explanation:
Alveolar ventilation (VA) is different from minute ventilation (VE) in that VA refers to the volume of air that reaches the alveoli and is available for gas exchange, while VE is the total volume of air entering and exiting the lungs per minute, including air that fills the anatomical dead space which does not contribute to gas exchange. The effectiveness of ventilation largely depends on alveolar ventilation rather than minute ventilation because it is the actual air that participates in exchanging oxygen and carbon dioxide with blood in the alveoli. Changes in the respiratory rate and tidal volume, due to various conditions, can affect both VE and VA differently.
At the alveolar level, the partial pressures of oxygen and carbon dioxide reflect the gas exchanges that are taking place. Pulmonary ventilation must be sufficient to create a high partial pressure of oxygen in the alveoli for proper gas exchange.