Your heart

Contrary to orthodox belief the heart does not pump blood through the system
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But rather receives it listens to it and send it back out again.
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It is an organ of perception. 
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According to what it senses about the blood, the heart produces a vast array of hormones.
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Many of them only recently discovered.
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That communicate with other parts of the body.
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Just as  its own cells are affected by exogenous hormones. 
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Most physiological descriptions of the heart liken it to a pump.
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But the heart does not provide the propulsive force for blood circulation at all. 
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It would be impossible for a 300gram organ to pump a viscous fluid through thousands of miles of small blood vessels. 
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In fact embryonic circulation begins before a functioning heart is even present.
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Possessing its own endogenous momentum sustained by its relationship to the entire body.
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The heart temporarily halts the flow, which expands the atrium before being released into the ventricle it is more similar to a hydraulic ram than a pump.
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With the addition of a twisting function to maintain the bloods spiralling motion.
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The spiral motion and discrete velocity being essential for different blood groups to reach their intended organ.
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The heart is indeed a wondrous organ and to date we still know relatively little about its more subtle workings.