THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The endocardium is composed of the endothelium and the subendothelial connective tissue layer. The subendocardium is found between the endocardium and myocardium and contains the impulse-conducting system.

Detailed explanation-2: -The epicardium, or the innermost layer of the pericardium, is the outermost layer of the heart itself. It is composed of mesothelial cells, fat, and connective tissue. It is adjacent to the myocardium, the middle muscular layer.

Detailed explanation-3: -Endocardium. The endocardium can be compared to the tunica intima of blood vessels. It forms the luminal surface of the heart and is composed of simple squamous epithelium. Deep to the endocardium is the subendocardial tissue, which contains loose vascularized connective tissue.