The heart is a muscular cone-shaped organ about the size of a clenched fist of the same person. It is located in the upper body (chest area) between the lungs, and with its pointed end (called the apex) downwards, forwards, and points towards the left. The main purpose of the heart is to pump up blood around the body. The Heart is divided into separate right and left sections by the interventricular septum, or "septum" when the context is clearly that of the heart. Each of these (right and left) sections is also divided into upper and lower compartments known as atria and ventricles, respectively. The four main chambres of the heart are Right Atrium Right Ventricle Left Atrium Left Ventricle .