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 ...
Laid end-to-end, an adult's arteries, veins and capillaries would stretch for about 100,000 miles - enough to wrap around the world nearly four times. Each 2.54 square centimetre (a square inch ...