Question

How are the lungs designed in human beings to maximise the area for exchange of gases?

Answer 1

Exchange of gases takes place between the blood capillaries that surround the alveoli and the gases present in the alveoli. Thus, alveoli are the site for the exchange of gases. The lungs get filled up with air during the process of inhalation as the ribs lift up and the diaphragm lowers and flattens out. The air that rushes inside the lungs fills the numerous alveoli present in the lungs.
Each lung contains 300-350 million alveoli. These numerous alveoli increase the surface area for gaseous exchange making the process of respiration more efficient.