ANATOMY

Detailed explanation-1: -The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striped (striated), and are under involuntary control.

Detailed explanation-2: -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-3: -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-4: -Cardiac muscle is made up of specialised cells called cardiomyocytes. These cells are sometimes called contractile myofibrils because they are long and cylindrical (shaped like a fibril) and they contract at a regular rate to keep blood flowing through the heart.