NEET PG DENTAL EXAM

Detailed explanation-1: -Gas exchange during respiration occurs primarily through diffusion. Diffusion is a process in which transport is driven by a concentration gradient. Gas molecules move from a region of high concentration to a region of low concentration.

Detailed explanation-2: -When blood returns to your lungs from the body, it has a lot of carbon dioxide and little oxygen. The carbon dioxide concentration is much greater in your blood than the alveoli. So, by the rule of diffusion, the carbon dioxide moves from the blood to the alveoli, where it can be exhaled through the lungs.

Detailed explanation-3: -Gas exchange by diffusion depends on the large surface area provided by the hundreds of millions of alveoli in the lungs. It also depends on a steep concentration gradient for oxygen and carbon dioxide.