Final answer:
The active respiratory surface area of the lungs, comprised of alveoli, is comparable in size to a tennis court when completely flattened. This extensive surface area facilitates rapid gas exchange of oxygen and carbon dioxide between the alveoli and the capillary network surrounding them.
Step-by-step explanation:
If you flattened the active respiratory surface area of your lungs, specifically the alveoli, it would be most comparable to the size of a tennis court. The lungs possess a remarkable surface area due to the presence of approximately 300 million alveoli per lung. These tiny air sacs, each about 0.1 mm in diameter, are the functional units where gas exchange occurs. Alveoli are lined with a mucus membrane and are surrounded by a network of capillaries. The thin walls of the alveoli and their close proximity to the capillary network facilitate the rapid diffusion of oxygen O₂ into the blood and the removal of carbon dioxide CO₂ from the blood.
The extensive surface area of the alveoli, combined with the structural arrangement of the capillaries and red blood cells, ensures efficient gas exchange. The large surface area is comparable to half a tennis court when combined across two lungs. This high surface area is vital for meeting the oxygen demands of the body and for the expulsion of carbon dioxide, a waste product of metabolism.