神經(jīng)組織主要由神經(jīng)細(xì)胞（即神經(jīng)元）及神經(jīng)膠質(zhì)細(xì)胞組成。神經(jīng)膠質(zhì)細(xì)胞在中樞神經(jīng)系統(tǒng)中數(shù)量極多，如按細(xì)胞核計(jì)數(shù)，則神經(jīng)膠質(zhì)細(xì)胞的數(shù)目約為神經(jīng)細(xì)胞的10倍；如按體積計(jì)算，神經(jīng)膠質(zhì)細(xì)胞與神經(jīng)細(xì)胞約各占腦容積的一半。神經(jīng)細(xì)胞被神經(jīng)膠質(zhì)細(xì)胞緊密地包圍起來(lái)，兩者關(guān)系密切。