How does the heart work?


Heart is one of the most important organs of our body. It acts as a pump for supplying oxygenated blood and nutrients to all parts of the body. It is cone-shaped and approximately similar to the size of human fist. Heart is located on the left of breastbone.

It has three layers called endocardium which is the innermost lining, myocardium, the middle one and pericardium, the outer one. Heart consists of four chambers two are on the left and two are on the right side of heart. The top chambers are known as right and left atrium. Both at the bottom are known as right and left ventricles. Septum separates left and right side of heart. These parts play important role in the proper functioning of heart. The main function of heart is to supply oxygenated blood to different parts of body.

Firstly the impure blood or oxygen lacking blood enters into the right atrium through the veins called inferior and superior vena cava. After that it goes to tricuspid valve and then to right ventricle. This ventricle contracts and pushes the blood to pulmonary valve which carries the impure blood to lungs where the oxygen again enters the blood and carbon dioxide is given out.

Now pulmonary vein carries the oxygenated blood to the left side of the heart. First it goes to the left atrium and then to left ventricle. When it contracts it pushes the blood to aorta through aortic valve. Aorta is a vessel that distributes the blood to the different organs and tissues.

Whenever the right or left ventricle is filled with blood both mitral and tricuspid valve closes so that the blood cannot flow back into the atrium during the contraction of ventricle. This process goes on till the person is alive.

How heart beat is caused?

The lining of all four chambers of heart are made up of special muscle because they have to contract and relax in the proper way and order so that the blood can be pumped with each single beat of heart.

Sino-atrial node is the natural pacemaker of heart present in the right atrium of heart which acts in regular intervals by giving an electrical impulse. It sends these impulses at the rate of 60 to 80 per minute while resting and more if you are exercising or doing hard physical work. The rate depends upon the fastness of work.

These impulses make both the atrium to contract which further allows the blood to move in the ventricles. Now the impulse is sent to atrio-ventricular node which is in the lower part of right atria. Here the impulse is halted which causes a slight delay. This AV node takes the impulse to ventricles and the blood is pumped out of the ventricles and goes to the body or lungs. The whole process is repeated with each and every impulse. This electrical impulse of the heart is the source that causes heartbeat.

Nearly 5 quarts of blood is pumped per minute and every single impulse causes the blood to circulate in the body and lungs.
Weight of female heart is 9 oz (255g) and that of a male is 10.5 oz (300g). Heart of normal person beats 72 times per minute. Variation in number of beats also happens depending on age, physical workout, health, fitness etc.

There can be some serious problems in the parts of heart which requires proper treatment. Severe damage in the heart can cause heart attack which may even lead to death.

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