ANATOMY

Detailed explanation-1: -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-2: -The arterioles branch into the capillary networks that supply tissues with oxygen and nutrients. The walls of arteries are thicker than the walls of veins, with more smooth muscle and elastic tissue.

Detailed explanation-3: -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. Explain that smoking harms your blood cells and blood vessels, including tiny capillaries.

Detailed explanation-4: -Blood travels from the heart in arteries, which branch into smaller and smaller vessels, eventually becoming arterioles. Arterioles connect with even smaller blood vessels called capillaries.

Detailed explanation-5: -Capillaries. The arteries eventually divide down into the smallest blood vessel, the capillary. Capillaries are so small that blood cells can only move through them one at a time. Oxygen and food nutrients pass from these capillaries to the cells.