The human heart is a muscular organ located in the chest, responsible for pumping blood throughout the body. It consists of four chambers: the two upper chambers called atria and the two lower chambers known as ventricles. The heart works continuously, supplying oxygen and nutrients to tissues while removing carbon dioxide and waste products. The heart is divided into two sides: the right side pumps deoxygenated blood to the lungs for oxygenation, while the left side pumps oxygen-rich blood to the rest of the body. The heart's rhythmic contractions are regulated by electrical signals, ensuring efficient circulation and overall health.