Final answer:
Zone 2 of pulmonary capillary perfusion is the region in the lungs where ventilation and perfusion are well-matched with an efficient diffusion of oxygen from alveoli to capillaries.
Step-by-step explanation:
Zone 2 of pulmonary capillary perfusion is the region in the lungs where both ventilation (movement of air) and perfusion (flow of blood) are well-matched. In this region, the oxygen pressure (Po₂) in the alveoli is higher (around 100 mm Hg) than the pressure in the capillaries (around 40 mm Hg). This pressure gradient allows for efficient diffusion of oxygen from the alveoli into the capillaries and subsequent binding to hemoglobin.