The heart wall is mad up of three different layers.

1. The 'endocardium' is a very thin smooth layer of cells, that resembles squamous epithelium. This membrane lines the interior of the heart. The valves of the heart are formed by reinforced folds of this material.

2. The 'myocardium' is the muscle layer of the heart, is the thickest layer.

3. The 'epicardium' forms the thin outermost layer of the heart wall and is continuous with the serous lining of the fibrous sac, that encloses the heart. These membranes together make up the pericardium. The serous lining of the pericardial sac is separated from the epicardium on the heart surface by a thin fluid- filled space.

──────────────────────────────────────────────────────────────────────────────────────────