Your heart is at the the center of your circulatory system. This system consists of a network of blood vessels, such as arteries, veins and capillaries. These blood vessels carry to and from all areas of your body.Capillaries- So small only one red blood cell can fit through it at a time. Smallest.Arteries-any of the muscular-walled tubes forming part of the circulation system by which blood (mainly that which has been oxygenated) is conveyed from the heart to all parts of the body.Veins- ny of the tubes forming part of the blood circulation system of the body, carrying mainly oxygen-depleted blood towards the heart.