Which term describes the process of breathing in and out?

The term that describes the process of breathing in and out is "ventilation." Ventilation encompasses both inhalation, which refers specifically to the act of taking air into the lungs, and exhalation, which is the process of expelling air from the lungs. Together, these actions form the complete cycle of ventilation, which is essential for gas exchange in the body, allowing oxygen to enter the bloodstream and carbon dioxide to be removed.

In this context, while inhalation and exhalation are components of the broader term, ventilation captures the entirety of breathing as a physiological process. Respiration, on the other hand, is often used to refer to the biochemical processes by which cells utilize oxygen and produce carbon dioxide, rather than the mechanical act of breathing itself. This distinction is key in understanding respiratory physiology and the terms related to it.