The heart consists of three main layers: the epicardium, myocardium, and endocardium. The epicardium is the outer layer, providing a protective covering. It also contains blood vessels and nerves that supply the heart. The myocardium is the thick, muscular middle layer responsible for the heart's pumping action. It contracts to circulate blood throughout the body. The innermost layer, the endocardium, lines the heart's chambers and valves, ensuring smooth blood flow and preventing clot formation. Together, these layers work harmoniously to maintain effective heart function.