Question

In which part of the circulatory system does the exchange of oxygen and dioxide take place between blood and cells?

Answer 1

The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.