THE CIRCULATORY SYSTEM PROCESS
The function of the circulatory system is nourish the cells of our organism with oxygen and nutrients and get rid of rejections substances.
It's composed by the heart, the arteries, the capillaries and the veins.
The heart is like a pump. The musculature of the heart makes that the blood exits with strength to the arteries, and goes to all the capillaries, that carries the blood to all the cells that exchange the nutrients with the rejections substances.
The circulatory system is a closed circuit, and it has got a double circuit.
The first circuit is the general circulation, where the circulation of the blood with oxygen goes to all the body and is returned to the heart. The other circuit is the pulmonary circulation where the circulation of the blood goes to the lungs, that introduces the oxygenated blood into the heart.
The heart, the "motor" of the circulatory system, it's divided in four cavities, two atriums and two ventricles. Between the atrium and the ventricle there are valves that regulate the blood flow. We also found these valves between the ventricles and the arteries.
The right atrium receives the blood that arrives from the vena cava (blood with rejections substances). Next, the blood passes to the right ventricle and is propel to the chest artery to go to the lung to be oxygenated (pulmonary circulation).
When the blood it's oxygenated returns to the heart trough the chest vein. After, it enters to the left atrium and next, enters to the left ventricle and exits propel to the aorta artery, to arrive to all the body cells.
The blood is propelled to the arteries with a lot of strength. This strength is called blood pressure. When the blood returns trough the veins the blood pressure is very small. For this reason, the veins have got some little valves that close the pass when the blood moves around. This permit that the blood returns to the heart.