What is the innermost layer of the heart referred to as?

The innermost layer of the heart is known as the endocardium. This delicate tissue lines the interior of the heart chambers as well as the heart valves, serving as a protective barrier. Its smooth surface helps to facilitate the flow of blood within the heart and minimizes the risk of blood clot formation by providing a non-thrombogenic surface.

The myocardium, which is another layer of the heart, consists of the muscular tissue that enables the heart to contract and pump blood, but it is not the innermost layer. The pericardium is a double-walled sac that surrounds the heart and serves to protect and lubricate it but is located outside of the myocardium and endocardium. The epicardium, on the other hand, is the outer layer of the heart, also part of the pericardium that adheres to the surface of the heart. Thus, the endocardium is correctly identified as the innermost layer, serving essential functions related to the heart's internal environment and functionality.