THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Myocardium-the middle, muscular layer. Endocardium-the inner layer.

Detailed explanation-2: -The endocardium is the innermost layer of the heart. It lines the inner surfaces of the heart chambers, including the heart valves. The endocardium has two layers. The inner layer lines the heart chambers and is made of endothelial cells.

Detailed explanation-3: -The endocardium consists of a single layer of endothelial cells lining the chambers of the heart. Occasionally, small amounts of smooth muscle can also be in the endocardium. Compared to the right atrium, the left atrium has a thicker endocardium because of high pressure from the pulmonary veins.