The structure and the function of the heart in the circulatory system
The circulatory system
The circulatory system is the system that transports the digested food, oxygen gas and the water to all the body cells and carries the wastes away from the body cells to special organs to get rid of them.
The heart is a muscular hollow organ equals about the size of your fist, and it locates inside the chest cavity between the two lungs, The heart pumps the blood continuously throughout the body, the four chambers of the heart are always full of the blood, and connected to the blood vessels.
The heart consists of four chambers located in two sides (the right side and the left side), The upper chamber in each side is called “atrium”, and the lower chamber is called “ventricle”.
There is a wall that separates between the right side of the heart and the left side of the heart, to prevent mixing of the blood in both sides.
There is a valve between each atrium and ventricle to allow the blood to flow from the atrium to the ventricle and prevents its returning back.
The heart normally pumps 4.5 to 5 liters of the blood per minute where this rate increases up to three times when exercising, The heart is about 350 grams in a man weighing 70 Kg.