THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -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-2: -The myocardium is the largest of the three layers, and contains cardiac muscle fibres, and loose endomysial connective tissue that contains lots of capillaries.

Detailed explanation-3: -Endocardium is the thin inner lining of the heart chambers and also forms the surface of the valves. Myocardium is the thick middle layer of muscle that allows your heart chambers to contract and relax to pump blood to your body.

Detailed explanation-4: -The epicardium is an epithelial layer, which in the mature vertebrate heart consists of a single-layered flat mesothelium connected to the myocardium by subepicardial connective tissue.