MUSCLE PHYSIOLOGY

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: -Histologically, the heart is mainly composed of cardiomyocytes and connective tissue. Dense connective tissue with elastic fibers is present in the cardiac/fibrous skeleton.

Detailed explanation-3: -Cardiac muscle, like skeletal muscle, is made up of sarcomeres that allow for contractility. However, unlike skeletal muscle, cardiac muscle is under involuntary control. The cardiac muscle is responsible for the contractility of the heart and, therefore, the pumping action.

Detailed explanation-4: -The heart wall is comprised of three layers, the epicardium (outer), myocardium (middle), and endocardium (inner). These tissue layers are highly specialized and perform different functions.