AP BIOLOGY

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: -The wall of the heart consists of three distinct layers-the epicardium (outer layer), the myocardium (middle layer), and the endocardium (inner layer).

Detailed explanation-3: -The main function of the myocardium is to facilitate the contraction and relaxation of the heart walls in order to receive and pump the blood into the systemic circulation. In addition, the myocardial cells provide a scaffold for heart chambers and conduct electrical stimuli.

Detailed explanation-4: -The correct option is A Cardiac muscles. Cardiac muscles: The walls of the heart is made up of cardiac muscles.

Detailed explanation-5: -(II) Heart wall-It consists of 3 layers, the serous membrane or epicardium (outer), cardiac muscle or myocardium (middle), and endocardium (inner).