The non-stop working pump is an amazing organ of the human body. Even when you are sleeping it goes on pumping blood to reach every part of your body to keep you alive and healthy. With every beat, the heart pumps one hundred cubic centimetres of blood. In one day about 10, 000 litres of blood is pumped through our blood vessels, which means that in an average life, a heart pumps about 250,000,000 litres of blood! and it never stops to rest!
What we call a heart-beat is one contracting and relaxing of the heart. During the contracting purified blood is pumped out, during the relaxing impure blood from the parts of the body enters.