Tiedemann K
Anat Embryol (Berl). 1982;163(4):403-16. doi: 10.1007/BF00305555.
The ectodermal and endodermal coverings of the allanto-amniotic membrane in cattle fetuses of various gestational ages have been studied by scanning and transmission electron microscopy. We have observed that the allantoic and amniotic epithelia have rather similar cells which are rich in filaments but poor in organelles. Neither epithelium reflects its different origin nor the differences in the composition of the two fetal fluids. Maturation changes occur in the pattern of the various surface specializations until midterm. Coral-like luminal outgrowths, which also contain organelles, were observed in both epithelia, whereas microplicae had formed only on fully differentiated amniotic cells. Interspersed smooth-surface cells in the allantoic epithelium that differ also in nuclear shape, glycocalyx, and mitochondria are regarded as a second cell type. Besides fluid-filled blisters and cornified pustules, the most typical feature of the amniotic epithelium is a rather regular lateral cell interdigitation with tongue-like lamellae of even thickness. Micropinocytotic vesicles are more frequent than in the allantois. Both epithelia possess similar tight junctions; no morphological or histochemical indications of an active sodium transport were evidenced.
运用扫描电子显微镜和透射电子显微镜，对不同孕周牛胎儿尿囊羊膜的外胚层和内胚层覆盖物进行了研究。我们观察到，尿囊上皮和羊膜上皮具有相当相似的细胞，这些细胞富含细丝但细胞器较少。两种上皮均未体现出其不同的起源，也未反映出两种胎儿液体成分的差异。直到中期，各种表面特化模式才会发生成熟变化。在两种上皮中均观察到了珊瑚状的管腔生长物，其中也含有细胞器，而微褶仅在完全分化的羊膜细胞上形成。尿囊上皮中散布着表面光滑的细胞，这些细胞在核形状、糖萼和线粒体方面也存在差异，被视为第二种细胞类型。除了充满液体的水泡和角质化脓疱外，羊膜上皮最典型的特征是相当规则的侧向细胞交错，形成厚度均匀的舌状薄片。微吞饮小泡比尿囊中更常见。两种上皮均具有相似的紧密连接；未发现有活性钠转运的形态学或组织化学迹象。
