Question

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

Answer 1

• Human lungs contain a highly branched network of respiratory tubes.
• The primary bronchus divides into secondary bronchi, tertiary bronchi, and then into numerous bronchioles.
• The bronchioles end in millions of tiny air sacs called alveoli.
• Alveoli are thin-walled and surrounded by a dense network of blood capillaries.
• They provide a very large surface area for the exchange of gases.
• Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli.
• The total surface area of the alveoli is about 70–100 m², which makes gas exchange highly efficient.