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 the 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 gram in a man weighting 70 Kg .