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How the Heart Works

The heart is an amazing and vital organ of our body that helps sustain life. This fist-sized organ is in simple word a "pump" which pumps oxygen and nutrient-rich blood throughout the body with the help of a network or veins and arteries. Heart has a complex internal structure and is divided into right side and left side. The right side has two chambers called the right atrium and right ventricle which collects oxygen-poor blood which then pumped into the lungs, where the oxygen is replenished. The left side of the heart is divided into the left atrium and left ventricle and these chambers collect oxygen-rich blood and pump it out to different parts of the body. The right and left sides of the heart work in tandem to ensure a continuous flow of blood to the lungs, and body. Large veins known as the inferior and superior vena cava empties the oxygen-poor blood from the body into the right atrium of the heart and as it contracts the blood flows from the right atrium into the right ventricle through the open tricuspid valve. When the ventricle becomes full, the tricuspid valve shuts and that prevents blood from flowing back into the atria through the ventricular contraction. After this the blood leaves the heart through the pulmonic valve, which then flows into the pulmonary artery and into the lungs where it is enriched with oxygen. This oxygen-rich blood is then emptied into the left atrium with the help of the pulmonary vein. As the atrium contracts the blood flows from the left atrium into the left ventricle through the open mitral valve. The mitral valve shuts when the ventricle is full thus preventing the blood from flowing backward into the atrium during ventricular contraction. During the contraction the blood goes out of the heart through the aortic valve, into the aorta and then is carried to different parts of the body. This pattern is followed repeatedly to ensure proper circulation of blood throughout the body.

The heart beats at the rate of 70-100 beats per minute making a lub-dub sound. The electrical system of the heart is the power source that makes the heart beat possible. The sinoatral node in the right atrium is heart's natural pacemaker and it generates an electrical impulse which causes the atria to contract and pump blood into the ventricles. This electrical impulse reaches the atrioventricular node and from there it moves to the ventricles through the atrioventricular bundle and then the ventricles contract to pump blood to the arteries. After this process the heart relaxes for a small period of time after which the beating begins again.