In the sequence of respiration in humans, which physiological step acts as the chronological link between the exchange of gases occurring across the simple squamous epithelium of the alveoli and the exchange of gases occurring at the systemic capillaries?

Step-by-step solution

Respiration in humans occurs in a specific sequence of five steps. The exchange of gases across the simple squamous epithelium of the alveoli represents the second step (alveolar diffusion). The exchange of gases at the systemic capillaries represents the fourth step (diffusion of O ₂ and CO ₂ between blood and tissues). The physiological step that chronologically and functionally links these two events is the third step, which is the transport of gases by the blood. Pulmonary ventilation is the first step (occurri