Wall Of The Heart Anatomy and Layered Structure

Humans are the evolved creatures with a well-developed set of organs for different functions that help the body be in a healthy state. The most important organ in the body is the human cardiovascular system which is the circulatory system or the blood-vascular system as it pumps the blood to the rest of the body. The heart is also a muscle and the muscular layer of the heart has thick heart walls that accommodate the arteries, veins and capillaries that pump blood and beats 60 to 80 times per minute. The beating of the heart indicates the function of carrying and delivering oxygen-rich blood to each cell and organ of the body. And the oxygen-deficient blood that reaches back to the heart via veins is again sent to the lungs in order to acquire more oxygen, this circulation is repetitive and goes on to keep us alive. 

Wall of the Heart 

The wall of the heart is a thick layer and can be three layers of the heart wall that comprises this wall. Each made up of different cells and all pertaining to different purposes that aid in the function of the heart. The layers of the heart wall can be divided into three layers as can be seen clearly from the image below. 

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The Layers of the Heart

The heart is but a muscle with various entry and exit points for the veins, capillaries, and arteries that helps in delivering oxygen and other nutrients to and from the heart. The heart also has four chambers: the left ventricles, right ventricles, right atrium and left atrium that help keep the pumping going and all this is possible with the support of the wall of the heart. 

The layers of the heart are divided into three layers: the outermost layer of the heart which is the epicardium, the muscular layer of the heart that is the middle layer called the myocardium and the innermost layer of the heart which is the endocardium layer. The heart is held by a pericardial double-walled sac called the pericardium, The pericardium’s outer wall is called the fibrous pericardium made up of connective tissue and the inner layer is the serous pericardium or serous visceral pericardium which is made up of serous membrane. Let us now take a look at the layers of the heart wall in detail. 

1. Epicardium - The epicardium is the outermost layer of the heart and also can be considered attached to the serous membrane of the pericardium layer. This is a thin elastic additional layer of protection from the trauma caused due to the probable friction between the pericardium and heart. It is made up of connective tissues and a layer of fat tissues as well, and elastic fibres and adipose tissue. Epicardium is the home to coronary blood vessels that supply oxygen to the heart via the coronary arteries.

Functions -

• It assists in the production of the pericardial fluid. 

• The friction is reduced as the pericardial fluid fills up the pericardial cavity thus protecting from trauma to the heart muscle. 

• Protects the inner layers of the heart from this trauma as well since the inferior wall of the heart epicardium is connected to the myocardium that is the muscular layer of the heart.  

2. Myocardium - The middle muscular layer on the outer and upper part is connected to the epicardium. It is the thickest layer of the heart wall. It is composed of cardiomyocytes that are specialised cardiac muscle cells that function as the other muscle in contraction and only differ in shape. The structure and shape differ as the specialised cardiac muscle has fewer nuclei and are shorter than the skeletal muscle. Even though it is the thickest layer the thickness also varies in degrees around the heart, it remains the thickest in the ventricular chamber region. 

Functions -

• The specialised myocardial cells and muscle fibres assist in cardiac conduction through a contraction.

• The thickness around ventricular walls is greater than the rest of the heart because the ventricles need the most power in carrying out their function of pumping the oxygenated blood to the other parts. 

• The myocardium supports the ventricular function by triggering the impulses to contract.

3. Endocardium - The inferior wall of the heart as it is in close alignment to the inner heart chambers and valves. The innermost layer of the heart is a thin inner layer composed of endothelial cells. The endothelial layer continuously covers the valves and chambers and even the major blood vessels that enter and leave the heart. 

Functions - 

• It acts as a barrier between the heart muscles or cardiac muscles and the blood. 

• The cardiomyocytes bathe in the extracellular fluid and it is possible because of the barrier created by the endocardium.

• The metabolic waste removal from heart tissues is regulated by the endocardial cells. 

• If by certain bacteria, fungi, or other microbes and infection is caused in the valves the endocardial layer is also infected. And it leads to endocarditis which is an inflammation of the endocardium and it can be fatal. 

Conclusion

The heart wall truly is the one that keeps the chambers and the other blood vessels intact so keeping it healthy through exercising regularly and having a good diet conscious is very crucial. The walls help the heart to be at its best performance level and if caused any harm due to overexertion or stress of the muscle, it can lead to severe damage. One must make informed and proper decisions for the heart to live a long and healthy life.