The Circulatory System
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is the course taken by the blood through the
arteries, capillaries, and veins and back to the heart. In humans, the
heart is made up of four chambers the right and left auricles, or atria,
and the right and left ventricles. The right side of the heart pumps
oxygen-poor blood from the cells of the ....
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.... from returning into the auricle by the tricuspid valve, which
completely closes during contraction of the ventricle. In its passage
through the lungs, the blood is oxygenated, then it is brought back to the
heart by the four pulmonary veins, which enter the left auricle. When this
chamber contracts, blood is forced into the left ventricle and then by
ventricular contraction into the aorta. The bicuspid, or mitral valve
prevents the blood from flowing back into the auricle, and the semilu ....
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Word count: 1335
Page count: 5 (approximately 250 words per page)
