Final answer:
The alveoli in the lungs greatly increase the surface area for gas exchange, comparable to the size of a tennis court. The thin walls of the alveoli and the close proximity of capillaries allow for rapid diffusion of oxygen and carbon dioxide.
Step-by-step explanation:
The alveoli in the lungs greatly increase the surface area for gas exchange between the lungs and bloodstream. In human lungs, there are approximately 300 million alveoli, providing a total surface area for gas exchange of up to 90 square meters. This is about the size of a tennis court.
The structure of the alveoli, capillaries, and red blood cells allows for rapid diffusion of oxygen and carbon dioxide. Oxygen from the air inside the alveoli is absorbed by the blood in the surrounding capillaries, while carbon dioxide is released from the blood into the alveoli. This exchange of gases occurs due to the thin walls of the alveoli and the close proximity of capillaries.