The human circulatory system consists of several components, but three key parts are:
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Heart: The heart is a muscular organ that pumps blood throughout the body. It has four chambers: the right atrium, right ventricle, left atrium, and left ventricle.
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Blood Vessels: These are the network of tubes through which blood flows. They include arteries, veins, and capillaries. Arteries carry oxygenated blood away from the heart, veins carry deoxygenated blood back to the heart, and capillaries allow for the exchange of gases, nutrients, and waste between blood and tissues.
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Blood: Blood is the fluid that circulates through the vessels, transporting oxygen, nutrients, hormones, and waste products. It consists of red blood cells, white blood cells, platelets, and plasma.