What are the three layers of the heart wall?

The three layers of the heart wall are the epicardium, myocardium, and endocardium.

The epicardium is the outermost layer of the heart and serves as a protective layer. It is a thin layer that also contains blood vessels and nerves supplying the heart. The myocardium, which is the middle layer, is made up of cardiac muscle tissue responsible for the contraction of the heart, allowing it to pump blood effectively. Finally, the endocardium is the inner layer that lines the chambers of the heart and covers the heart valves. This layer is crucial for ensuring smooth blood flow within the heart and preventing blood clots.

The other options include components that do not accurately represent the structure of the heart wall. For example, the pericardium is a protective sac surrounding the heart but is not a part of the heart wall itself. Additionally, the term "endomysium" refers to a component of skeletal muscle tissue and is not relevant to the heart's anatomy. Understanding these distinct layers and their roles is fundamental for comprehending heart function and cardiovascular health.