The human heart and its structure

Human Heart


The human heart is a hard working pump. It circulates blood throughout the humans body. It pumps five liters (5 liters) blood every minute. About 8,000 (eight thousands) liters of blood move through 96,000 km ( ninety six thousands kilometers) of blood vessels every day. The heart of an adult human beats about 70 (seventy) times per minute. It beats more than one lac (100,000)  times per day. The human heart beats more than 2.6 billion times in a 70 years of life period. Human heart never fatigues.

Structure of human heart


Human heart is composed of three basic types of tissues:

1. Epicardium


The outermost protective covering of human heart is termed as epicardium. It is composed of fibrous connective tissues.

2. Myocardium


Most of the human heart ( maximum part) is composed up of cardiac muscles. These muscles are called myocardium.

3. Endocardium


It forms the inner side of human heart. Endocardium is composed of connective tissues and endothelium. Endothelium is a single covering of epithelial cells. It lines the chambers of heart and lumen of blood vessels.

The left and right halves of the human heart have two separate pumps.

Atria


Human heart has two thin walled chamber's called atria.

Ventricles


Human heart has two thick walled chamber's are known as ventricles.

AV Valves


(Av valves is abbreviated as atrioventricular valves)

Valves are present between the atria and ventricles. They are collectively called as AV-valves.

Tricuspsid valve


It is present between the right atrium and right ventricle.

Bicuspid valve


It is present between the left atrium and left ventricle.

Pulmonary semi lunar valve


It is present at the exit of the right ventricle.

Aortic semi lunar valve


It is present at the exit of the right ventricle. The changing in blood pressure opens and closes these valves. These human heart valves keep blood moving in one direction. They inhibit back-flow of blood.

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