What is the term for the process of taking in oxygen and expelling carbon dioxide from the lungs?

The term that describes the process of taking in oxygen and expelling carbon dioxide from the lungs is respiration. This process is essential for maintaining the proper function of the body's cells, as oxygen is a critical component for cellular processes that generate energy. During respiration, the lungs facilitate the exchange of gases; oxygen from the air enters the bloodstream, while carbon dioxide—a waste product of metabolism—is removed from the bloodstream and exhaled.

This respiratory action occurs in a two-part process: inhalation (where oxygen is brought into the lungs) and exhalation (where carbon dioxide is expelled). It is distinct from other processes such as circulation, which pertains to the movement of blood and nutrients throughout the body, or digestion, which is related to the breakdown of food for nutrient absorption. Metabolism refers to the chemical reactions that occur within the body to maintain life, which includes both the consumption of oxygen and the production of carbon dioxide but is not limited to just the respiratory process. Therefore, respiration specifically encompasses the exchange of these gases in the lungs.