The heart has four separate chambers. The upper two chambers are called the right and left atria (RA and LA). The atria are the receiving chambers for blood returning from the body and the lungs. The wall dividing the two atria is called the atrial septum. The lower two chambers are the right and left ventricles (RV and LV). The ventricles are muscular chambers responsible for pumping blood to the body and lungs. The wall dividing the two ventricles is called the ventricular septum.

The heart functions to pump blood to the lungs and the body. In order to pump, the heart requires an electrical impulse just like any other muscle in the body.

The heart itself requires blood to work properly just like any other organ in the body. The heart muscle is fed with blood by the coronary arteries. The coronary arteries originate from the aorta just above the takeoff from the heart itself.