What is the process called when oxygen is transferred from air in the alveoli to the blood?

The process of transferring oxygen from the air in the alveoli to the blood is known as external respiration. This occurs in the lungs, specifically in the alveoli, where oxygen molecules in the air are absorbed by the blood in the capillaries surrounding these tiny air sacs.

During external respiration, the oxygen concentration in the alveoli is higher than that in the blood, which allows for the diffusion of oxygen into the bloodstream. This process is essential for maintaining sufficient oxygen levels in the body and is a key component of the respiratory system's function.

In contrast, internal respiration refers to the exchange of gases between the blood and the body's cells, where oxygen is delivered to tissues and carbon dioxide is picked up from the cells. Cellular respiration is the process by which cells utilize oxygen to produce energy from glucose. Gas exchange is a broader term that describes the overall process of exchanging oxygen and carbon dioxide, but in the context of this question, external respiration specifically refers to the transfer of oxygen from the alveoli into the blood.