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?神經(jīng)由神經(jīng)元等一些結(jié)構(gòu)組成,神經(jīng)系統(tǒng)分為中樞神經(jīng)系,(包括腦和脊髓),周圍神經(jīng)系,包括腦神經(jīng),脊神經(jīng),植物性神經(jīng)(其中有交感神經(jīng)和副 交感神經(jīng)).外周神經(jīng)支配軀體和內(nèi)臟,又分傳出和傳入神經(jīng).神經(jīng)元分感覺,中間,運(yùn)動(dòng)神經(jīng)元,結(jié)構(gòu)上分細(xì)胞體和突起,突起又分軸突和樹突,通常神經(jīng)纖維指 的是軸突.在身體體表和體內(nèi)有專門的感受器.通過感受器神經(jīng)纖維受到刺激而興奮.神經(jīng)元與神經(jīng)元,神經(jīng)元與效應(yīng)器相接觸的部位稱突觸,神經(jīng)沖動(dòng)經(jīng)突觸傳遞 到另一個(gè)神經(jīng)元,經(jīng)過多次交換神經(jīng)元,達(dá)到大腦特定區(qū)域.簡(jiǎn)單來說,受到外界刺激通過神經(jīng)傳入大腦. |
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