PATHOLOGY

Detailed explanation-1: -The walls of the alveoli share a membrane with the capillaries. That’s how close they are. This lets oxygen and carbon dioxide diffuse, or move freely, between the respiratory system and the bloodstream.

Detailed explanation-2: -The body structure that is the site for actual diffusion of respiratory gases are the alveoli and the capillaries.

Detailed explanation-3: -Capillary Exchange Mechanisms Diffusion, the most widely-used mechanism, allows the flow of small molecules across capillaries such as glucose and oxygen from the blood into the tissues and carbon dioxide from the tissue into the blood.