What is the name of the tissue that lines the heart?

The tissue that lines the heart is called the endocardium. This thin layer of tissue is located on the inner surface of the heart chambers and is composed of endothelial cells, which provide a smooth lining to help reduce friction as blood flows through the heart. The endocardium also plays a crucial role in maintaining the health of the heart by providing a barrier to infection and contributing to the regulation of heart function.

In contrast, the myocardium is the thick muscular layer responsible for the heart's contractile action. The pericardium is the protective sac surrounding the heart, and the epicardium is the outer layer of the heart wall, which is also part of the pericardial sac. Understanding these distinctions helps clarify why the endocardium is specifically identified as the lining tissue of the heart.