Name the basic components of the circulatory system.
The heart is the organ which pumps the blood through the circulatory system. Arteries are the vessels that carry blood away from the heart. Veins are the vessels that carry blood toward the heart. Capillaries are the tiny vessels that connect the arteries to the veins. The capillaries run from the smallest arteries, called arterioles, to the smallest veins, called venules. Substances transported by the blood are exchanged between blood and tissue in the capillaries.
