Blood vessels carry blood throughout your entire body, powering your organs and muscles and keeping you alive. That takes a lot of work, and therefore you need a ton of blood vessels. The blood-vessel system is made up of two types of vessel: veins and arteries. Veins carry deoxygenated blood back to the heart, where it is then pumped to the lungs and filled with oxygen. Arteries carry oxygen-rich blood to the muscles and organs. There are so many blood vessels in your body that if you laid them end to end, they would cover over 60,000 miles - more than half of all the paved roads in Mexico.