Which organ is responsible for circulating blood throughout the body?

The heart is the organ responsible for circulating blood throughout the body. It serves as a muscular pump that continuously contracts and relaxes to propel blood through a vast network of arteries, veins, and capillaries. This circulation is vital as it delivers oxygen and nutrients to cells while removing carbon dioxide and other waste products. Blood flow from the heart is organized into two primary circuits: the pulmonary circuit, which transports deoxygenated blood to the lungs for oxygenation, and the systemic circuit, which distributes oxygenated blood to all body tissues.

The brain, while crucial for controlling many body functions, does not directly circulate blood. The lungs play a key role in oxygenating blood but do not circulate it; their function is primarily respiratory. The liver, important for metabolism and detoxification, plays a role in processing blood but does not circulate it. Thus, the heart's unique structure and function make it the central organ in the circulation of blood throughout the body.