Adult Echocardiography Practice Exam

What is the inner layer of the cardiac wall called?

1. Myocardium

2. Endocardium

3. Epicardium

4. Visceral layer

The correct answer is: Endocardium

The inner layer of the cardiac wall is known as the endocardium. This thin, delicate layer lines the interior of the heart chambers and covers the heart valves. Its primary function is to provide a smooth surface for blood to flow, reducing turbulence within the heart. The endocardium is composed of endothelial cells and connective tissue, allowing it to maintain a good interface with the blood while also being involved in the functioning of the heart valves. In this context, the myocardium, which is the muscular middle layer of the heart wall, is responsible for the heart's contraction and pumping ability. The epicardium is the outer layer of the heart wall that is also referred to as the visceral layer of the serous pericardium, providing a protective covering. The term "visceral layer" is a broader term that refers to the layer that surrounds the organs in the body cavity, including the heart. While both the epicardium and visceral layer pertain to the external layers of the heart, it is the endocardium specifically that is identified as the inner layer. Thus, the endocardium's unique role in lining the heart chambers makes it the correct answer to the question.