sturge_weber
Forum Guru
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can someone explain the defecation reflex
what happens if the external sphincter gone, what if the pelvic nerve, and what happens when the pudendal nerve gone, and what happens when the internal anal sphincter gone
very perplexing ....
plzzzz reply asap
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| reet
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defecation reflex occurs when rectum distented--
1, internal sphincter RELAXES
2, EXternal sphincter CONTRACTS
3, and when urge to defecate is percieved
PELVIC NERVE gives parasympathetic to int sphincter(SMOOTH MUSCLE) - helps in RELAXATION --if DAMAGED nerve-- NO ANAL SPHINCTER RELAXATION OCCURS.AND URGE TO DEFECATE ALSO DOESNT OCCUR( cuz sensory affernt from rectum to spinal cord)
pudendal nerve-- SYMPATHETIC innervation to ext sphincter ( striated muscle)-helps in contractions..SO IF DAMAGED NERVE---no contraction of external sphincter.
hope it helps... plz correct me if anything wrong
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| sturge_weber
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hey thanks reet...
so that means if pelvic nerve gone, no internal sphincter relaxation and no urge to defecate
if pudendal nerve gone, no urge to defecate
thanks i got it now
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| Geroo
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pudendal nerve carries somatic innervation to EAS not sympathetic
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| msyamp
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yes there is no sympathethetic innervation to anal spincter i think
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