Short note||Functional anatomy of the human heart:

Introduction to heart:

Heart is an important organ of the cardiovascular system. Heart is a muscular organ that pumps blood throughout the circulatory system.

The human heart weighs approximately 300g and it consists of two halves right and left , both structurally and functionally. This is situated in the mediastinum in between the two lungs.

Diagram of the human heart,Image by-Wapcaplet, Source , License- CCBY-SA3.0

Chambers of the heart:

There is present an inflow chamber and an outflow chamber in each half of the heart. The inflow chamber is known as atrium and the outflow chamber is known as ventricle.

Thus there is present four chambers in the heart.

Right side of the heart:

There is present two chambers in the right side of the heart these are right atrium and right ventricle.

Right atrium:

Right atrium is a thin walled ,low pressure chamber. Right atrium receives deoxygenated blood via two large veins(superior and inferior vena cavae) from the tissues of the entire body .

Superior vena cavae , that returns venous blood from the head ,neck and upper limbs.

And inferior vena cavae that returns venous blood from the lower parts of the body.

Blood from the right atrium passes into the right ventricle via right atrioventricular orifice, which is gurded by tri-cuspid valve.

In the right atrium there is present a pacemaker known as sinoatrial node ,which produces rhythmic impulses for heartbeat and AV(atrioventricular node)that conducts these impulses to the ventricles.

Right ventricle:

From the right atrium ,blood ,then enters the right ventricle through the tricuspid valve. From the right ventricle pulmonary artery (left pulmonary artery and right pulmonary artery)arises,which carries the blood from the right ventricle to the lungs.

Heart structure and functions

Left side of the heart:

Left side of the heart has two chambers ,left atrium and left ventricle.

Left atrium :

Left atrium of the heart is a thin walled and low pressure chamber. It receives oxygenated blood from the lungs via four pulmonary veins (two right pulmonary veins and two left pulmonary veins).

This is the only exception in the body , where an artery carries venous blood and vein carries the arterial blood . Blood from the left atrium of the heart then enters the left ventricle through the left AV orifice which is gurded by mitral valve(bicuspid valve).

Left ventricle:

Left ventricle receives blood from the left atrium and pumps out into the systemic circulation through the aorta. Aortic valve is present at the junction of left ventricle and the ascending aorta.

Valves of the heart:

There is present four valves in the human heart ,two AV valves and two semilunar valves . Atrioventricular valves are present in between the atria and ventricle.

Semilunar valves are present at the opening of blood vessels arising from ventricles. These valves allow unidirectional flow of blood.

AV valves of the heart:

There is present two atrioventricular valves namely right and left atrioventricular valves. Right atrioventricular valve is also known as tricuspid valve and left atrioventricular valve is known as bicuspid valve or mitral valve.

The AV valves open towards the ventricles and close towards the atria. But during ventricular contraction these valves are closed and thus prevent back flow of blood from the ventricles to atria.

Right atrioventricular valve is made up of three cusps(anterior, posterior and septal) and left atrioventricular valve is made up of two cusps (anterior and posterior).