Anatomy and Physiology II Practice Test

What is the exchange of gases between the blood and air in the lungs called?

1. External respiration

2. Pulmonary ventilation

3. Internal respiration

4. Alveolar exchange

The correct answer is: External respiration

The process of gas exchange between the blood and the air occurs in the lungs and is termed external respiration. This process involves the transfer of oxygen from the inhaled air into the bloodstream and the removal of carbon dioxide from the blood into the air within the lungs. External respiration specifically refers to the physiological changes that allow for the exchange of gases at the alveolar level, where oxygen diffuses into the blood and carbon dioxide diffuses out. Other terms in the context of respiratory physiology serve different functions. Pulmonary ventilation refers to the mechanical process of breathing, which includes inhalation and exhalation but does not encompass gas exchange itself. Internal respiration, on the other hand, involves the exchange of gases at the tissue level, where oxygen is delivered from the blood to the tissues and carbon dioxide from the tissues enters the blood. Alveolar exchange can be seen as a descriptive term for the process taking place at the alveoli but not the overarching term that encapsulates the entire process of gas exchange with respect to the blood and the air. Therefore, the correct identification of this fundamental process as external respiration is vital to understanding how oxygen and carbon dioxide are managed in the body.