Circulatory System

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The circulatory system is the major transport system within the human body and consists of blood, arteries, veins, capillaries and the heart. The system services all the organs of the body including the lungs, intestines, liver and kidneys as well as the rest of the human body.

All mammals and birds have a system of double circulation. Blood travels from the right side of the heart (right ventricle) to the lungs. Here it exchanges carbon dioxide for oxygen and becomes bright red, before returning to the left side of the heart (left atrium). The second part of the process involves the blood being pumped from the left ventricle around the body. Here, it loses the oxygen it has carried and gains carbon dioxide before returning to the right atrium of the heart, for the process to begin again.

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