Each 2.54 square centimetre (a square inch) of human skin has six metres (20ft) of blood vessels. Veins hold about 65 per cent of the body's blood and have one-way valves tohelp blood move.

Your circulatory system is made up of three parts: the heart, blood vessels and the blood itself. Your heart keeps all the blood in your circulatory system flowing. The blood travels through a ...

the lymphatic system. Considerable adaptability built into vertebrate circulatory systems: Considerable variation in blood vessels, as seen in shark Due to developmental origin of blood vessels: many ...

This short film offers a look at respiration and a tour around the circulatory system and digestive system in the human body, through blood vessels and into mitochondria. There is a detailed ...

these so-called static models fail to reproduce what occurs in vivo since they lack a key component of the circulatory system: the physical forces exerted by blood flowing through the blood vessels.