Question: What is the difference between an artery and a vein?

Chris Cooper answered on 16 Mar 2010:

An artery carries blood away the heart. A vein carries blood to the heart. An artery is thicker as it has to cope with a much higher blood pressure. Veins include valves to stop the blood flowing in the wrong direction. Arteries don’t need them as the pressure is so much higher the blood flows much faster and is not in danger of reversing.