ANATOMY

Detailed explanation-1: -The cardiac muscle is responsible for the contractility of the heart and, therefore, the pumping action. The cardiac muscle must contract with enough force and enough blood to supply the metabolic demands of the entire body. This concept is termed cardiac output and is defined as heart rate x stroke volume.

Detailed explanation-2: -Cardiac muscle (or myocardium) makes up the thick middle layer of the heart. It is one of three types of muscle in the body, along with skeletal and smooth muscle. The myocardium is surrounded by a thin outer layer called the epicardium (AKA visceral pericardium) and an inner endocardium.

Detailed explanation-3: -Cardiac muscle tissue is only found in your heart, where it performs coordinated contractions that allow your heart to pump blood through your circulatory system.

Detailed explanation-4: -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-5: -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.