What is heart
What is heart?
The heart is the main and special organ of blood circulation system. It is muscular, hollow, contractible cone shaped organ which is situated in a portion of tissues which is called mediastinum at the middle of both lungs behind the sternum in the chest and by displacing towards some left side along with some crookedness. Because of displacing towards some left side, its one-third portion is towards the right side from the middle line of the body and two-third portion is situated towards the left side. The upper portion of the heart is some broad which is called base and it is bent towards some right side. The lower pointed portion is called apex which is bent some left side and some forward and is situated on the diaphragm. The boundary of apex reaches at the intercostals of fifth and sixth ribs. This is the portion where one feels the sensation of heart throbbing.
The shape of heart is like a fist of a person. Normally its length is 12 centimeter and breadth is nine centimeter (5x 3.5 inch). The weight of the heart in adult people is between 250 to 390 grams and 200 to 275 in adult women.
The wall of the heart is made of seven layers-