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Question
How are the lungs designed in human beings to maximize the area for exchange of gases?
Solution 1
Lungs contain millions of alveoli which provide a surface for the exchange of gases. An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli. The oxygen from the breath, diffuses into the blood and CO2 from the blood brought from the body, diffuses out into the air.
Solution 2
- Human lungs contain a highly branched system of respiratory tubes. A primary bronchus splits into secondary bronchi, which then form tertiary bronchi. Each tertiary bronchus further divides into bronchioles that end in alveoli. Alveoli are small, rounded, thin-walled pouches with a network of capillaries.
- Gas exchange occurs in the alveoli, which is why each alveolus is considered a miniature lung. The alveoli offer a large surface area for gas exchange. Oxygen diffuses from the alveoli into the pulmonary capillaries, while carbon dioxide diffuses from the capillaries into the alveoli. The total surface area of the alveoli in human lungs is estimated to be about 100 m².
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