The heart is a muscular organ having the size of a closed fist that functions as the body’s circulatory pump. The heart is located in the thoracic cavity medial to the lungs and posterior to the sternum in a double-layered sac called the pericardium.
The heart has four chambers:
- The right atrium receives blood from the veins and pumps it to the right ventricle.
- The right ventricle receives blood from the right atrium and pumps it to the lungs, where it is loaded with oxygen.
- The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle.
- The strongest chamber which is the left ventricle pumps oxygen-rich blood to the rest of the body.