Blood Circulation Essay

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Circulatory System is the combined function of the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the body and carry away waste products. The circulatory system increases the flow of blood to meet increased energy demands during exercise and regulates body temperature. Also, when foreign substances or organisms invade the body, the circulatory system quickly sends disease-fighting elements of the immune system, such as white blood cells and antibodies, to places under attack. In the case of injury or bleeding, the circulatory system sends clotting cells and proteins to the affected site, which quickly stop bleeding and promote healing. The circulatory system plays an important role in controlling body temperature. The blood supplying the muscles with oxygen and nutrients absorbs much of this heat and carries it away to other parts of the body. If the body gets too warm, blood vessels near the skin enlarge to diffuse excess heat outward through the skin. In cold atmospheres, blood vessels constrict to retain heat. The heart, blood, and blood vessels are the three main elements that make up the circulatory system. The heart acts as the engine of the circulatory system. It then divides into four chambers, the left ventricle, the right atrium, the left atrium, and the right ventricle. The walls of the chambers are made of muscles called myocardium. Myocardium contracts to pump blood. The pumping action of the heart occurs in two stages for each heartbeat. Diastole when the heart is at rest, and systole, when the heart contracts to pump deoxygenated blood toward the lungs and oxygenated blood to the body. Blood consists of three types of cells, red blood cells which carry oxygen, disease-fighting white blood cells, and blood-clotting platelets. All three of these blood cells are carried through plasma. Plasma is
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