The heart is actually made of cardiac muscle, which is a specialized type of muscle tissue found only in the heart. It's not made up of individual, distinct muscles like your biceps or triceps.

However, you can think of the heart as having several layers of cardiac muscle:

* Myocardium: This is the thickest layer of the heart wall, and it's responsible for the heart's pumping action. It contains the specialized muscle cells (cardiomyocytes) that contract to pump blood.

* Endocardium: This thin, inner layer lines the chambers of the heart and covers the valves.

* Epicardium: This is the outer layer of the heart, also known as the visceral pericardium. It helps protect the heart and lubricates its movement within the chest cavity.

While we don't talk about specific "muscles" in the heart like we do in other parts of the body, the myocardium is the essential part that makes the heart beat.