What is the process called in which gases are exchanged in the lungs?

The process in which gases are exchanged in the lungs is known as diffusion. In the context of respiration, diffusion refers to the movement of oxygen from the alveoli (tiny air sacs in the lungs) into the blood in the capillaries, while carbon dioxide moves from the blood into the alveoli to be expelled from the body. This exchange occurs due to the concentration gradients of these gases—the oxygen concentration is higher in the alveoli than in the blood, while carbon dioxide concentration is higher in the blood than in the alveoli. The effectiveness of this diffusion process is crucial for maintaining proper respiratory function and ensuring that the body receives adequate oxygen while removing carbon dioxide.

Inspiration and expiration are the processes of inhaling and exhaling air, respectively, but they do not directly describe the exchange of gases; rather, they facilitate the conditions under which diffusion occurs. Absorption generally refers to the uptake of substances by a surface or organism, which is not the primary mechanism for gas exchange in the lungs.