Which term describes the outermost layer of the heart wall?

The outermost layer of the heart wall is referred to as the epicardium. This layer is also known as the visceral pericardium and serves as a protective covering for the heart. It is a thin layer of serous membrane that contains cells facilitating the smooth movement of the heart within the pericardial cavity, minimizing friction caused by the heart's contractions.

Understanding the structure of the heart is crucial, as each layer plays a specific role in heart function. The myocardium, which is the muscular middle layer, is responsible for the heart's contraction and pumping ability. The endocardium lines the heart's chambers and valves, providing a smooth surface for blood flow. The pericardium, although protective, is a fibrous layer that encapsulates the heart as a whole rather than being a part of the heart wall itself. This distinction highlights the specific function and location of the epicardium as the outermost layer.