Respiration is defined as?

Respiration is defined as?

• A. Movement of air between lungs and environment
• B. Process of gas exchange
• C. Blood flow through capillaries
• D. Oxygen transport in blood

Answer: (B)

Gas exchange between the air in the lungs and the blood is what respiration refers to. Oxygen moves from the alveolar air into the blood, while carbon dioxide moves from the blood into the alveolar air to be exhaled. This diffusion-driven exchange is the defining action of respiration. Movement of air into and out of the lungs is ventilation, not respiration. Blood flow through capillaries is circulation, and oxygen transport in blood describes carrying oxygen after loading, not the exchange at the lungs. So the correct concept is the process of gas exchange.

Gas exchange between the air in the lungs and the blood is what respiration refers to. Oxygen moves from the alveolar air into the blood, while carbon dioxide moves from the blood into the alveolar air to be exhaled. This diffusion-driven exchange is the defining action of respiration. Movement of air into and out of the lungs is ventilation, not respiration. Blood flow through capillaries is circulation, and oxygen transport in blood describes carrying oxygen after loading, not the exchange at the lungs. So the correct concept is the process of gas exchange.