Question

Exchange of gases between the blood and the tissues of the body takes place by which of the following mechanism?

• A. Breathing
• B. Diffusion
• C. Active transport
• D. Counter-current exchange

Answer 1

The correct option is B

Diffusion

Diffusion is the process by which exchange of gases takes place between the blood and body tissues. Oxygen is transported to each and every cell of the body by the blood. Then oxygen diffuses from blood to the tissue fluid and finally to the cells and carbon dioxide from the cells diffuse into the tissue fluid and finally into the blood. This exchange happens along the concentration gradient of the gases i.e. from a region of their high concentration to a region of their low concentration.