山羊胎儿肺泡上皮的电镜观察

Electron microscopic study on the alveolar epithelium of the goat fetus

对山羊胎儿肺泡上皮进行透射电镜观察 ,结果表明 :腺状期 (第 6～ 12周 ) ,终蕾上皮细胞胞质内线粒体、粗面内质网及核糖体随着胎龄增加而逐渐增多 ,胞核向细胞顶端移行 ;小管期 (第 13～ 14周 ) ,终蕾上皮由单层柱状上皮逐渐演变为立方形的原始肺泡上皮 ,胞质内线粒体、粗面内质网及核糖体较发达 ;囊状期 (第 15周 ) ,肺泡上皮细胞开始分化为 型细胞和 型细胞 ,嗜锇小体首次出现 ,气血屏障开始建立 ;肺泡期 (第 16～ 2 2周 ) ,以肺泡的形成和分化为主 , 型细胞的超微结构特征为嗜锇小体出现 ,核糖体显著增多 ,粗面内质网池扩张 ,线粒体膨大 ,出现多泡体。

Lungs of goat fetus (6-22 wks) were observed with transmission electron microscopy.The result shows:At glandular stage(6-12 wks),the nuclei of the terminal bud columnar epithelial cell transfers to the top of the cells gradually.Mitochondria,rough endoplasmic reticulum and ribosome are all in the top of the cells and increased in number with the development of the lungs.At canalicular stage(13-14 wks),the terminal buds epithelium differenttiates from single walled columnar epithelium into cuboid primitive alveoli epithelium.Mitochondria,rough endoplasmic reticulum and ribosome develop dramatically in the cells.At saccular stage (15 wk),part of the primitive alveoli epithelium differentiates into flattened type Ⅰ alveolar cells and cuboid type Ⅱ alveolar cells.The osmiophilic bodies were first observed in type Ⅱ alveolar cells and the blood air barrier began to establish.At alveolar stage (16-22 wks),more primitive alveolar epithelial cells developed and differentiated into flattened type Ⅰ alveolar cells and cuboid type Ⅱ alveolar cells.The differentiation markers of type Ⅱ cells are as followings:The osmiophilic bodies and ribosome are seen abundently,rough endoplasmic reticulum pools expand and floccular materials appear.Mitochondria expanded.Multivesicular bodies are observed.