Heart pumps blood around the body.
from the left auricle the oxygenated blood is pushed down into the left ventricle which is further transported to all the organs of the body by the arteries. Exchange of blood takes place and goes back to the heart through the veins. The right auricle receives the deoxygenated blood and pushes it down to the right ventricle. This blood then reaches the lungs and is oxidized. This blood reaches the heart and the cycle starts up all again.