What are Cardiac Muscles?

What are Cardiac Muscles?

Cardiac muscle also known as heart muscle or myocardium is one of three types of muscle tissue found in vertebrates. The other two are skeletal and smooth muscle. It is an involuntary, striated muscle that makes up the majority of the heart’s wall tissue. Between the outside layer of the heart wall known as the pericardium and the inner layer known as the endocardium, the cardiac muscle creates a thick middle layer with blood supplied via the coronary circulation. Individual cardiac muscle cells are connected together by intercalated discs, and the extracellular matrix is made up of collagen fibres and other components.

Cardiac muscle contracts similarly to skeletal muscle, although there are a few key differences. The release of calcium from the cell’s internal calcium storage known as the sarcoplasmic reticulum, is triggered by electrical stimulation in the form of a cardiac action potential. Excitation-contraction coupling occurs when calcium levels rise, causing the cell’s myofilaments to slip past each other. Cardiomyopathies, or diseases of the heart muscle, are extremely important. Ischemic disorders, such as angina and myocardial infarction, are caused by a reduced blood flow to the muscle.

Clinical Significance:

Cardiomyopathies are a major clinical concern, and they are the leading cause of death in developed countries. Ischaemic heart disease, in which the heart’s blood flow is diminished, is the most prevalent ailment affecting cardiac muscle. Atherosclerosis narrows the coronary arteries, causing ischemic heart disease. The syndrome of angina pectoris might develop if these narrowings become severe enough to partially impede blood flow. During exercise, this creates chest pain that is eased by rest. A myocardial infarction or heart attack happens when a coronary artery gets unexpectedly constricted or totally blocked, halting or severely limiting blood flow through the vessel. A cardiac muscle region may become irreversibly scarred and injured if the blockage is not removed promptly by medication, percutaneous coronary intervention, or surgery.

Despite having a normal blood supply, heart muscle can be injured. Myocarditis is a condition in which the heart muscle becomes inflamed. It is most commonly caused by a viral infection, but it can also be caused by the body’s own immune system. Factors like alcohol, long-term high blood pressure or hypertension, or persistent irregular heart racing can all harm the heart muscle. Cardiomyopathies are heart muscle illnesses that produce abnormally thick, excessively big, or abnormally stiff heart muscle. Some of these diseases are caused by genetic mutations and can be passed down through generations. Many of these disorders, if serious enough, can damage the heart to the point where it loses its ability to pump blood. Heart failure occurs when the heart is no longer able to pump enough blood to meet the body’s needs.

Components of heart muscles:

Intercalated Discs:

Small connections between heart muscle cells (cardiomyocytes) are known as intercalated discs.

Gap Junctions:

The intercalated discs include gap junctions. When one cardiac muscle cell is induced to contract, the stimulation is transferred to the next cardiac cell through a gap junction. This makes it possible for the muscle to contract in a coordinated manner.


Desmosomes, like gap junctions, are located within intercalated discs. During a contraction, they assist in holding the heart muscle fibres together.


The nucleus is responsible for the control of the cell. It contains the entire genetic material of the cell. Skeletal muscle cells can have numerous nuclei, whereas cardiac muscle cells usually only have one.


One of the most common disorders that can impair your cardiac muscle tissue is cardiomyopathy. It’s a condition that makes your heart work harder to pump blood. Cardiomyopathy can be classified into numerous types:

Hypertrophic Cardiomyopathy: The heart muscles grow and thicken for no obvious reason in hypertrophic cardiomyopathy. It usually occurs in the heart’s bottom chambers, known as the ventricles.

Dilated Cardiomyopathy: It causes the ventricles to enlarge and become feeble. This makes it difficult for them to pump, which further disrupts the rest of your heart from pumping blood.

Restrictive Cardiomyopathy: It causes the ventricles to stiffen, preventing them from filling to capacity.

Arrhythmogenic Right ventricular dysplasia: Your right ventricle’s heart muscle tissue is replaced with fatty or fiber-rich tissue. Arrhythmia, or an abnormal heart rate or rhythm, can result as a result of this.

Cardiomyopathy does not always cause symptoms. However, it can occasionally result in:

  • Breathing difficulties
  • fatigued
  • Swollen ankles, feet, legs, abdomen


One of the three forms of muscle in your body is cardiac muscle tissue. It’s only found in your heart, where it helps keep your heart beating by coordinating contractions. Regular exercise and the correct diet will aid you in keeping your cardiac muscles healthy and avoid mild or severe cardiac diseases.