Which term best describes moving air in and out of the lungs?

• A. Ventilation
• B. Oxygenation
• C. Perfusion
• D. Diffusion

Answer: (A)

Ventilation is the movement of air into and out of the lungs. This mechanical process creates the airflow that brings oxygen-rich air to the alveoli and removes carbon dioxide from the body. Oxygenation refers to the oxygen content in the blood after oxygen has diffused from the alveoli into the capillaries; perfusion describes the flow of blood through the lung's vessels to receive that oxygen; diffusion is the actual transfer of gases across the alveolar-capillary membrane. Since the question focuses on the act of moving air itself, ventilation is the best term.