Blood Supply of Heart

About Blood Supply of Heart

The heart is a major organ of the human body which is responsible for the circulation of the blood. Blood circulation in the body ensures that every cell of the organ receives nutrients and oxygen supply to perform its metabolism. To understand the blood supply of the heart it is important to understand the location of the heart, anatomy of the heart, the vasculature of the nerve which answers questions like which artery supplies blood to the heart.  This article dwells with the intricacies of blood supply of heart anatomy and functioning, which arteries supply blood to heart, the circulation system of the heart known as coronary circulation.


Heart 

The location of the heart can be defined by understanding the cavity it is present in. The heart is present in the thoracic cavity, which is posterior to the sternum, inferior to the diaphragm. It is located in between the lungs. The heart is made up of myocardium muscle, this muscle has exceptionally high thickness thus the heart can not work with the normal vasculature of the circulation. The blood supply of the heart is also known as coronary circulation and the artery that supplies blood to the heart is known as the coronary artery. The heart is the four-chambered organ. It is divided into two atria and two ventricles.

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Valves

There are four major valves present in the heart they are called, atrioventricular valve and the semilunar valve. Each of these valves is prest in pair thus forming 4 valves. 


The atrioventricular valve is also known as the mitral valve, they are present in the left and right atrioventricular junction. The left atrioventricular valve has two openings that are bicuspid and the right atrioventricular valve is known as the tricuspid valve because of three openings. It is important to note that the valves of the heart open in only one direction, thus allowing the blood to flow into a singular direction of circulation.


The semilunar valves guide the movement of blood during ventricular relaxation. They are present at the junction between the ventricle and outflow vessel. The outflow blood vessels are aortic and pulmonary vessels.

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Heart Wall

The heart wall can be defined as the muscular structure of the heart. The heart wall has 4 layers pericardium, epicardium, myocardium, and endocardium. The pericardium is the outermost layer of the heart wall, it is the layer in which arteries supply blood to the heart. It has a fibrous sac-like structure from the outside and the inner surface is generally parietal. Epicardium is the layer just below the pericardium, between both these layers there is a presence of the cavity; this cavity is known as the pericardial cavity. It is a fluid filled cavity. This layer, the epicardium, is also known as the visceral layer of the pericardium. The myocardium is the layer that is responsible for the contraction and relaxation of the atrium and ventricle, thus ensuring the blood supply of the heart. It has a modification known as an intercalated disk, which is specialized to the cardiac muscle only, it ensures the connection between the left and right ventricle and similarly left and right atrium. It is important to note that valves lack this intercalated disk. The blood vessels responsible for the blood supply of heart protrudes into this layer.

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Coronary Arteries

The blood supply of the heart is mediated by the arteries that specialized for circulation according to the blood supply of heart anatomy, it is because of the thickness of the cardiac muscle. Now the question arises which artery supplies blood to the heart. The answer to this question is coronary arteries. The blood supply of the heart is mediated by the coronary artery; these arteries are divided into two main classes: the left coronary arteries and the right coronary arteries. This complete circulation including the venous supply of the heart is known as coronary circulation. 


The left coronary artery divides into the left anterior descending and circumflex branches,  Both the arteries originate from the coronary Ostia. Coronary Ostia is the opening of the base of the aorta, they are located behind the aortic valve leaflets. The coronary arteries because they surround the epicardium are known as epicardial coronary vessels. These coronary vessels have a special feature of low vascular resistance as compared to normal blood vessels. The microcirculation of the blood is achieved at the level of small arteries and arterioles. They are the region that performs maximum exchange of oxygen and nutrients, thus they are the vital site of regulation, regulation of the blood flow is primarily achieved here.


Left coronary artery- according to the pattern of blood supply of heart anatomy, the left coronary artery divides into two main branches. One of the branches is named as circumflex artery while the other is named as Left Anterior Descending artery (LAD). left coronary arteries are comparatively larger than the right coronary arteries, they arise from the left aortic sinus. It appears in the mid between the pulmonary trunk and the left auricle. At this, it bifurcates to give an interventricular branch. The circumflex artery is the farther artery. From the interventricular point, it runs to the anterior coronary sulcus. It finally terminates by anastomosing by the right coronary artery. According to blood supply of heart anatomy, the left artery covers the regions of the left atrium, ventricles, (the greater part of the left ventricle and a smaller part of the right ventricle), anterior part of the interventricular septum, and AV bundle.


Blood Supply of Heart Diagram:

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Right coronary arteries further bifurcate into the right marginal artery and posterior descending artery. They are distributed in ventricles but to be noted that they are majorly present in the right ventricle and comparatively less in the left ventricle. They do not provide blood to the SA node, the SA node is supplied with the left coronary artery.


Anatomic Region of the Heart

Associated Coronary Artery

Anteroseptal

Left anterior descending

Inferior 

Right coronary

Anterolateral 

Circumflex artery

Anteroapical 

The left anterior descending  distal part

Posterior 

Right coronary artery

FAQs (Frequently Asked Questions)

Q.1. Which Arteries Supply Blood to the Heart?

Ans: The coronary arteries supply blood to the heart. They form the coronary circulation system, it also incorporates the venous supply of heart.

Q.2. What is the Role of the Mitral Valve?

Ans: They are the atrioventricular valve that allows the blood to come into the ventricular section of the heart leading to ventricular relaxation and atrial contraction.