When does blood flow from veins to arteries?

Your body has an amazingly complex and delicate system of blood vessels, carrying blood to every nook and cranny, and then returning to the heart. These vessels are called arteries and veins and they are both tubes made up of four different layers. The arteries carry the blood away from the heart and the veins return it.

The vein frequently anastomose (or join together) with each other so that the blood flow can alter direction. This is caused if there is any constriction or pressure from movement of muscles or ligaments.

Fact File:

Just over half of blood is plasma, a pale yellow, sweet-smelling, sticky fluid. It contains hundreds of dissolved substances, from sugars for energy, to hormones, to wastes like carbon dioxide.

 

Picture Credit : Google