AP BIOLOGY

Detailed explanation-1: -Capillaries are the smallest blood vessels in the body. How small are they? About ten of them equal the thickness of one human hair, and most are so small that only one blood cell can pass through them at a time.

Detailed explanation-2: -Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins). The primary function of capillaries is the exchange of materials between the blood and tissue cells.

Detailed explanation-3: -Capillaries: These tiny blood vessels have thin walls. Oxygen and nutrients from the blood can move through the walls and get into organs and tissues. The capillaries also take waste products away from your tissues. Capillaries are where oxygen and nutrients are exchanged for carbon dioxide and waste.

Detailed explanation-4: -An arteriole (är-’tir-ē-, ōl) is a very small blood vessel that branches off from your artery and carries blood away from your heart to your tissues and organs. Arterioles are small arteries that link up to capillaries, which are smaller yet.