AP BIOLOGY

Detailed explanation-1: -Answer. Answer: c) Endomyosin is not a layer of the heart.

Detailed explanation-2: -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.

Detailed explanation-3: -The endocardium is the innermost layer of the heart and lines the chambers and extends over projecting structures such as the valves, chordae tendineae, and papillary muscles.

Detailed explanation-4: -The outer layer of the heart wall is the epicardium, the middle layer is the myocardium, and the inner layer is the endocardium.

Detailed explanation-5: -The walls of the heart are composed of three layers: Epicardium-the outer layer. Myocardium-the middle, muscular layer. Endocardium-the inner layer.