Enteric nervous system
<p>June 1, 2019, 4:18 PM</p>
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<p>ENS one of main divisions of Autonomic nervous system ANS.</p>
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<p>ENS called the SECOND BRAIN (500 million neurons!!!)</p>
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<p>can act indep. of sympathetic and parasym. nervous system.</p>
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<p>derived from Neural crest cells.</p>
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<p>0.5% of the number of neurons in the brain.</p>
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<p>spinal cord has only 100M neurons; gut has 5X as many and</p>
<p>2/3 as many as th whole nervous system of a cat!!!</p>
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<p>30 neurotransmitters!!! most are identical to CNS: ACh, DA and 5HT.</p>
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<p>more than 90% of the body's serotonin is in the gut!!!! and</p>
<p>50% of the body's dopamine = DA.</p>
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<p>has support cells similar to astroglia.</p>
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<p>and a diffusion barrier around capillaries surrounding ganglia, similar to blood-brain barrier.</p>