The heart is a muscle located in the middle of the chest under the ribcage, states the National Heart, Lung, and Blood Institute. It pumps blood throughout the entire body through a pumping action that occurs when its electrical system signals its walls to contract, creating heartbeats.
The heart includes four sections, called chambers, according to the National Heart, Lung, and Blood Institute. The upper chambers are called atria, while the lower chambers are known as ventricles. The heart also has four valves, which make sure that the blood only flows in one direction: in or out.
When the heart muscle contracts, the chambers shrink and push oxygen-rich blood into the blood vessels, explains the National Heart, Lung, and Blood Institute. When the heart relaxes, the chambers expand again and allow the return of oxygen-poor blood. If the heart stops its pumping, the blood is unable to carry the oxygen and nutrients that the body's organs need to function optimally. Blood circulation is important for expelling carbon dioxide, the body's waste product, through the lungs.
The human heart beats approximately 100,000 times per day, delivering about 2,000 gallons of blood through the arteries, veins and capillaries, which comprise an approximately 60,000 mile-long network, states WebMD. The heart is the core of a healthy human body's optimal performance.