Each square inch of human skin consists of 6m (20ft) of blood vessels. Veins hold about 65 pc of the body's blood and have one-way valves to help blood move. Capillaries, which carry blood to our ...

There are three types of blood vessel: arteries, veins and capillaries. The heart is a muscular organ that pumps blood around your circulatory system. The circulatory system is the heart and all ...