the walls of the capilleries and alveoli are very thin why do they need to be thin?

Answer 1

To allow for diffusion.

Oxygen and CO2 must pass across the alveoli. Oxygen and nutrients pass one way through a capillary, a whole range of waste products including CO2 and uric acid pass the other way.

Answer 2

The thin wall needs to be thin so that the bigger particles of air can be diffused through the layers. In the air we're breathing, oxygenation and deoxygenation takes place in the alveolis so that they won't be trapped and cause congestion. Also, thin walls serve as a wet layer so that oxygen gets easily dissolved and oxygenation takes place even more effective. Hope this helps.

Answer 3

Capilliries are the smallest blood vessels.. Exchange of nutrients from blood to tissues and waste products from tissues to blood occurs through capilliries.. Thats why they are thin.. To facilitate this process.. Similarly, Alveoli are involved in exchange of gases between blood and air in the lungs.. Thin wall facilitates this purpose..

Answer 4

Hi. Thin membranes allow materials to pass through more freely.

Answer 5

If they were thick they would consitute far too much volume. There are miles of them in the human body. And since blood pressure in such minute vessels is minimal, they have no reason to be thick.

Answer 6

To allow gas exchanges with the blood red cells.

Answer 7

because if they were thick, the heart would have to pump harder, and we would suffocate from the less space our lungs had to expand and contract. plus, the thinner the better.

Answer 8

Because that's how GOD made us.