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 Sympathetic effects  

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Hi everybody! I have a problem, can't find the right answer..... If sympathetic system decreases motility and secr. of GI tract, why people have diarrhea when they are nervous (for example- right before taking Step 1smiling face) and if sympathetic system causes vasoconstriction, why boys turn red when they see a girl they like (and vice versa)? In both cases symp. system activated, so what's happening than????raised eyebrow
I'd appreciate your replies.nod


well bekind, the only thing i can try to answer is the first one, when u r stressed, sympathetic system fires so on GI that would be a decreased motility but the organism has to respond in order to lower sympathetic activity so it increases parasympathetic and decreases sympathetic which was an initial response then by activating and increasing parasympathetic you'll have an increased motility and relaxation of the sphincters. wink


my dear its because GIT has some sympathetic innervation that secrets serotonin or something similar...but not the usual lady nor-epi...becasue of the different chemical cubstance the action is reversed...

For the second is about blushing... there are sympathetic nerves which has cholinergic secretion... i think...these are present in cranial nerves... thats the reason when you are like Blush!!!

please correct me if im wrong.

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