The main organ responsible for pumping blood in the human body is the heart. This muscular organ functions continuously to circulate blood throughout the body, supplying oxygen and nutrients while removing waste products. It has four chambers: the right and left atria, and the right and left ventricles. The heart operates through a complex electrical conduction system that coordinates its rhythm and contractions. Maintaining a healthy heart is crucial for overall bodily function, as it ensures efficient blood flow and support for all organ systems.