In each cubic millimetre of blood, there are more than five million red blood cells, thousands of white cells and 250,000 to 450,000 platelets for blood clotting. Every second, 2.5 million new red ...

white blood cells, platelets and plasma. Blood vessels - Tubes that carry blood around the body. Cardiovascular system - Another name for the circulatory system, see below. Circulatory system - A ...

Save guides, add subjects and pick up where you left off with your BBC account. blood a pump (the heart) to push the blood around the body a system of tubes to contain the blood (arteries, veins ...

Blood is three times thicker than water and the average person has about five litres (or nine pints) of it in their body. Of the 50-75 trillion cells in the body, half are red blood cells.