Question

Why do arteries have tough elastic walls? What is the function of capillaries? Why are capillaries more narrow compared to arteries?

Answer 1

Thick walls of arteries help them to resist the pressure of flow of blood in them. Arteries are elastic so that it can produce enough pressure to push the blood and help it flow through them. Arteries are the first vessels that the heart pumps blood through, arteries experience the highest blood pressure, so they have thick elastic walls to endure the high pressures. These large arteries expand when the pressure of the blood pressure rises and then retreat when the heart relaxes between beats to provide a smooth flow of blood throughout the body.

Microscopic capillaries aids and serves as the location for the exchange of gases and nutrients between blood and cells of the tissues. The capillary walls are very thin and made up of a single layer of endothelial cells, which are very thin flattened cells that line the inner walls of all of the blood vessels as well. Capillaries don’t have to face the pressure as compared to the arteries so they are lot less thick and also much narrower as they have to reach to the cells and serve like the alleyways that extend and branch into every tissue of the body, which ensure that every cell has a blood supply and oxygen.