HEART

Heart
The organs that pumps the blood in blood vessels is called heart. Where is heart located? Put your hand on the upper left side of your chest. Do you feel something beating? The organ which is beating is your heart. What is the shape of the heart? The heart somewhat cone-shaped. The size of human heart is about the size of the first. It is present in the chest cavity between the two lungs. It is a muscular organ. The heart enclosed in a thin double-layered transparent membrane called pericardium.
Internal structure of human heart:

Source o Photo
Internally, the heart of four chambers. The upper two chambers are called atria and the lower two chambers are called ventricles. The atria are divided into left atrium and right atrium. The ventricle are also divided into right ventricle and left ventricle. Atria are thin walled chambers as compared to ventricles. Left ventricle is thicker than the right ventricle. The left atrium opens into the ventricle. The right atrium opens into the right ventricle. The flow of blood from atria to ventricles is regulated by valves which prevent the backflow of the blood
All data collected from my book of science
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