Which term describes the process of air leaving the lungs?

Which term describes the process of air leaving the lungs?

• A. Inhalation
• B. Inspiration
• C. Diffusion
• D. Expiration

Answer: (D)

Air leaving the lungs is expiration (also called exhalation). After air is drawn into the lungs during inhalation, the diaphragm and chest muscles relax, the lungs recoil, and air is pushed out. In normal breathing this is a passive process, though it can be active when a person exhales forcefully. In contrast, inhalation or inspiration refers to taking air into the lungs, and diffusion is the gas exchange that happens at the alveolar membranes, not the act of breathing out.

Air leaving the lungs is expiration (also called exhalation). After air is drawn into the lungs during inhalation, the diaphragm and chest muscles relax, the lungs recoil, and air is pushed out. In normal breathing this is a passive process, though it can be active when a person exhales forcefully. In contrast, inhalation or inspiration refers to taking air into the lungs, and diffusion is the gas exchange that happens at the alveolar membranes, not the act of breathing out.