ANATOMY

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 thickest in the left ventricle, as the left ventricle must create a lot of pressure to pump blood into the aorta and throughout systemic circulation.

Detailed explanation-3: -Cardiac muscle cells are located in the walls of the heart, appear striped (striated), and are under involuntary control.

Detailed explanation-4: -The myocardium is mainly made up of two types of cells: cardiomyocytes and fibroblasts. Fibroblasts are distributed between cardiomyocytes, along with extracellular matrix (ECM), blood vessels, lymphatic vessels, and nerve endings.

Detailed explanation-5: -Tunica Media (Myocardium) The tunica media layer is called the myocardium. The myocardium is the largest of the three layers, and contains cardiac muscle fibres, and loose endomysial connective tissue that contains lots of capillaries.