Final answer:
The heart functions as a sophisticated pump, with the right side pumping blood to the lungs (pulmonary circulation) and the left side supplying oxygen-rich blood to the rest of the body (systemic circulation). Its muscular structure contracts involuntarily to eject blood into the major vessels, much like a mechanical pump.
Step-by-step explanation:
The heart is often compared to a pump because of its role in circulating blood throughout the body. It has two distinct sides, each functioning as a separate pump. The right side of the heart pumps blood through the pulmonary circulation, which means it takes oxygen-poor blood and forces it into the lungs to pick up oxygen. The left side of the heart then pumps the oxygen-rich blood through systemic circulation to supply the tissues and organs of the body.
The heart's structure as a muscle allows it to contract and develop pressure, ejecting blood into the major vessels like the aorta and pulmonary trunk. While the term 'pump' might evoke images of mechanical devices, the heart is a sophisticated muscular pump that operates involuntarily and rhythmically, driven by specialized muscle cells called cardiomyocytes.