What is the process of gas exchange between the lungs and the blood called?

The process of gas exchange between the lungs and the blood is known as external respiration. This occurs in the alveoli, where oxygen from the air enters the bloodstream while carbon dioxide, a waste product of metabolism, is expelled from the blood into the lungs to be exhaled. This exchange is fundamental for maintaining the body’s oxygen levels and removing carbon dioxide, thereby supporting cellular functions throughout the body.

Ventilation refers to the physical act of breathing—moving air into and out of the lungs—but does not encompass the actual exchange of gases that takes place in the alveoli. Internal respiration, in contrast, pertains to the exchange of gases between the blood and the body's tissues, where oxygen is delivered to cells and carbon dioxide is collected for removal. Cellular respiration is a completely different process that takes place at the cellular level, involving the conversion of biochemical energy from nutrients into ATP, alongside the production of carbon dioxide as a byproduct.