Blood

Blood is made up of four parts:

Part	Function
Red blood cells	Transporting from the
Plasma	Carries dissolved foods from the and to the
Platelets	Form a (scab), together with from the plasma at the site of a wound .
White blood cells	of the body. They produce and remove microbes and dead tissue.

Blood travels through the blood vessels, of which there are 3:

Blood Vessel	Description
Arteries	elastic walls Carry blood away from the pressure - flow pulse No Valves
Veins	walled Carry blood into the pressure - flow pulse Has to prevent back flow
Capillaries	Very small blood vessels between Allows of substances needed by the cells and the removal of products

The heart has its own blood vessels known as the coronary blood vessels. They provide the oxygen and glucose to the heart and remove the waste, just like any other muscle. If there is a blockage of the coronary artery then the heart will not get the oxygen it needs and so stop pumping. This is known as a ''.