NEET BIOLOGY

Detailed explanation-1: -The alveoli present in the lungs have thin walls composed only of a single layer of cells in order to minimize the diffusion distance. Their walls are moist which helps the gases to diffuse better. They are richly supplied with blood capillaries to ensure the efficient exchange of gases with the bloodstream.

Detailed explanation-2: -Breathing in and out (a ventilation mechanisms) maintains a steep concentration gradient between the oxygen (and carbon dioxide) in the alveoli and the blood so that the rate of diffusion is faster.

Detailed explanation-3: -Each alveolus is cup-shaped with very thin walls. It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood.

Detailed explanation-4: -Thin lining: the lining of the alveoli is very thin so that gases can quickly diffuse through it.