THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The muscle layer of the heart is termed the myocardium and is made up of cardiomyocytes. The myocardium is found in the walls of all four chambers of the heart, though it is thicker in the ventricles and thinner in the atria.

Detailed explanation-2: -The walls of the heart are composed of three layers: Epicardium-the outer layer. Myocardium-the middle, muscular layer. Endocardium-the inner layer.

Detailed explanation-3: -The wall of the heart separates into the following layers: epicardium, myocardium, and endocardium. These three layers of the heart are embryologically equivalent to the three layers of blood vessels: tunica adventitia, tunica media, and tunica intima, respectively.