The heart is a pumping system which takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body). The heart is about the size of a fist but delivers a more powerful punch. Fortunately, it contains a buffer zone to decrease the force of these beats, or we would be shaken by each one. This buffer zone also protects themycontentbreak heart from outside injury and keeps it from scraping against the chest wall. Myth has it that the heart is the seat of the emotions, but it is actually a pump which circulates the blood throughout the body. The Medical Dictionary reports that the heart beats more than 2.5 billion times in an average lifetime.