Human heart :- The human heart is a muscular organ that pumps blood throughout the body. It has four chambers: two atria (upper) and two ventricles (lower). Its primary function is to circulate oxygen-rich blood to organs and tissues and return oxygen-poor blood to the lungs for oxygenation. The heart also helps maintain blood pressure and supports the body’s metabolic processes. It functions through a series of electrical signals that coordinate heartbeats, ensuring efficient blood flow and proper nutrient delivery.