Pearse 1969年首次提出APUD细胞系统起源于神经外胚层,一些学者用胚胎移植方法,已经证明甲状腺滤泡旁细胞、成黑色素细胞和颈动脉体的Ⅰ型细胞都起源于神经外胚层,但迄今未能证明胃肠和肺的内分泌细胞也起源于神经外胚层。 中间丝是高等动物真核细胞质内独特的细丝系统。中间丝可分五种类型,不同类型中间丝的正常分布有各自的组织特异性,根 Pearse first proposed in 1969 APUD cell system originated in neuroectoderm, some scholars using embryo transfer method, it has been demonstrated thyroid follicles, melanocytes and carotid body type I cells have originated in the neuroectoderm, but so far Endocrine cells that can prove gastrointestinal and pulmonary also originate in neuroectoderm. The middle filament is a unique filament system in the higher animal eukaryotic cytoplasm. Intermediate silk can be divided into five types, the normal distribution of different types of intermediate silk have their own tissue-specific, root