Which layer of the heart covers its outer surface?

The epicardium is the layer of the heart that covers its outer surface. It is a thin layer of tissue that forms the outermost layer of the heart wall, providing a protective covering. The epicardium is also part of the pericardium, which has an outer fibrous layer and an inner serous layer. The inner layer of the pericardium is actually the epicardium.

In contrast, the myocardium is the middle layer of the heart, composed primarily of cardiac muscle and responsible for the heart's contraction. The endocardium, on the other hand, is the innermost layer that lines the heart chambers and valves. Understanding these distinct layers is crucial for comprehending the anatomy and functionality of the heart.