论文部分内容阅读
小鼠胚胎第12天至生后7天的肺组织,隔天取材,共15例,常规电镜标本制作,透射电镜观察,探讨胎肺发育过程中肺泡上皮细胞的超微结构变化.观察结果表明:胚胎第12～14天(相当于人胎肺的假腺期)肺内均为管状“肺泡”,由形态相同的柱形细胞围成,核椭圆形,核膜平整,有1-2个核仁.细胞内含高尔基氏体、线粒体、粗面内质网和糖原.细胞表面有微绒毛,细胞之间有连结复合体.胚胎第16～18天,胞质内出现大量的糖原颗粒.胚胎第19天(相当于人胎肺的原始肺泡期),肺泡上皮细胞多为立方形,出现Ⅱ型肺泡细胞,其特征为表现有微绒毛,胞质内糖原减少,出现椭圆形板层小体,长约1～2μm,外有界膜,内含平行排列的板层,肺泡腔内偶可见板层小体.同时,肺内支气管上皮分化出纤毛细胞,其胞质电子密度低,纤毛的基粒处有线粒体.新生 1～4天,肺泡上皮仍以Ⅱ型细胞为主,Ⅱ型细胞内板层小体及线粒体数目增多,线粒体基质较致密.开始出现少量扁形的I型肺泡细胞.致新生7天,肺泡上皮才分化为以I型细胞为主.结论:胚胎18～19天以前胎肺内以形成结构分化为主,胚胎19天是Ⅱ型肺泡细胞分化的关键时期,而Ⅰ而型
The lung tissues of the mouse embryos from the 12th day to the 7th day after birth were harvested from the next day for a total of 15 cases and were made by conventional electron microscopy and transmission electron microscopy to investigate the ultrastructural changes of the alveolar epithelial cells during fetal lung development. : Embryos 12 to 14 days (equivalent to the human fetal lung pseudo-gland period) lungs are tubular “alveoli” surrounded by the same shape of cylindrical cells, nuclear oval, nuclear membrane formation, 1-2 Nucleolus.The cells contain Golgi apparatus, mitochondria, rough endoplasmic reticulum and glycogen.The surface of the cells have microvilli, cells have a link between the complex embryos on the first 16 to 18 days, the cytoplasm of a large number of glycogen Granules.At embryonic day 19 (equivalent to the primary alveolar stage of human fetal lung), most of the alveolar epithelial cells were cuboidal with Type II alveolar cells characterized by microvilli, reduced cytoplasmic glycogen, and oval Lamellar body, about 1 ~ 2μm, outside the world membrane, containing the parallel arrangement of the plate layer, alveolar cavity can even see the lamellar body.At the same time, the lung bronchial epithelial differentiated ciliated cells, the cytoplasmic electron density Low, ciliated mitochondria mitochondria .New 1 to 4 days, alveolar epithelium is still type Ⅱ cells, type Ⅱ cell inner plate Small number of mitochondria and mitochondria, mitochondrial matrix is more dense began to appear a small amount of flat type I alveolar cells.New 7 days, alveolar epithelial differentiation to type I cells.Conclusion: embryos 18 to 19 days before fetal lung To form the main structural differentiation, embryonic day 19 is a key period of type II alveolar cell differentiation, and type Ⅰ