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理解控制不同肌肉的不同大脑区域.  作者-拉贾·纳拉扬. Raja Narayan 创建




we can think of the nervous system as split up into two other parts there's going to be an autonomic nervous system branch and as the name kind of sounds like this is your automatic control that's the involuntary parts that we talked about from above beside that there's also going to be a control that we exert and so that's going to be called the somatic nervous system so that's something that we control somatic nervous system underneath the autonomic classification you can break this up into two other parts one is called the sympathetic nervous system and we sort of alluded to that above when we were talking about the sympathetic ganglia that were part of involuntary control in addition we also have a parasympathetic nervous system that sort of sits in a checks and balances position with the sympathetic nervous system and that's how we break this up the somatic nervous system is just the somatic nervous system so it has just sort of one function and it's trying to control voluntary muscle so the neurotransmitter that we use here which you may recall and I'll put this in parenthesis is asset eel choline asset eel choline and we abbreviate that a CH for asset eel choline what about the neurotransmitters that are used by the sympathetic and the parasympathetic nervous system we actually sort of know them already at least for the sympathetic nervous system and we can come up with it and the way you know them is if you think about what the sympathetic nervous system does because I'm sure you've heard of this phrase called your fight and flight response fight or flight and so that's when you're in a dire situation and your body senses oh I may die in any second now I need to do something to get out of here and so you activate the sympathetic nervous system so that you can achieve fight or flight you start pumping adrenaline through your body and you get your heart to beat faster so you can pump more oxygen to your legs to help you run quicker and get away so that's fight and flight and so I mentioned adrenaline which is an endocrine hormone that's secreted to help with this but it also has a neurotransmitter friend that does the same thing and so the neurotransmitter friend that I'm gonna write up here it's not adrenaline but it's nor adrenaline starts with an N and another term for that is nor epinephrine nor epinephrine I'll write it out nor epinephrine or nor adrenaline and so that's the neurotransmitter that's used by the sympathetic nervous system what about the parasympathetic nervous system well oddly enough it actually uses the same one that the somatic nervous system does and the way that you can sort of differentiate this from the sympathetic nervous system is that while the sympathetic nervous system is for these super hardcore intense moments where it's fight or flight the parasympathetic nervous system is a little more chill this is for rest and digest so when you're going to sleep and you're trying to relax so your heart rate could lessen and your muscles and your heart aren't contracting as quickly or if you just ate a big meal and you need to digest that food the parasympathetic nervous system will tell the stomach to churn that food up so you could digest it in your intestines as you also propel it along with the smooth muscle in there so that's achieved by acetylcholine all right so that's the two major divisions of the central nervous system autonomic and somatic