ANATOMY

Detailed explanation-1: -In the walls of the heart, there are two thin layers of epithelial and connective tissue that form a sandwich around a thick layer of muscle called the myocardium. The powerful contractions of the myocardium pump blood through the circulatory system.

Detailed explanation-2: -The endocardium is the thin membrane that lines the interior of the heart. The myocardium is the middle layer of the heart. It is the heart muscle and is the thickest layer of the heart.

Detailed explanation-3: -The muscles of the heart, termed the myocardium, make up the middle and thickest layer of the heart wall. This layer lies between the single-cell endocardium layer, which lines the inner chambers, and the outer epicardium, which makes up part of the pericardium that surrounds and protects the heart.

Detailed explanation-4: -Your heart is surrounded by a double-layered membrane, called the pericardium or pericardial sac.

Detailed explanation-5: -The myocardium is the middle layer that is composed of contractile tissues. The endocardium is the innermost layer and composes the valves, inner lining of the chambers, and contains vessels and nerves.