The cardiovascular system is responsible for moving blood to and from the heart. It has three parts: the heart, the blood and the blood vessels. The heart uses two pumps to circulate blood through our blood vessels: one to send oxygenated blood to the body and the other to send deoxygenated blood back to the lungs to receive oxygen.
The cardiovascular is a closed system, which means that the blood never leaves the blood vessels and heart. Nutrients, dissolved gases like oxygen, and waste products can move into and out of the bloodstream, but the blood is meant to stay in the system.
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