Demir R
Acta Anat (Basel). 1980;106(1):18-29. doi: 10.1159/000145165.
Human placenta samples obtained at 4, 6, 8 and 10 weeks of gestation and at full term were studied by transmission electron microscopy (TEM). The chorionic villi at early stages of gestation exhibited abundant microvilli on the free surface of the syncytium. The chorionic villi at full term were covered by syncytium which bore short microvilli on its free surface. The syncytial cells were remarkably higher in density than Langhans' cells. In the earlier period of gestation, a dividing membrane was noticed in the inside of the syncytial cells. The cytoplasm of the syncytial cell contained comparatively small mitochondria, well-developed endoplasmic reticulum cells, ill-developed Golgi systems, electron-dense lipoid droplets and plenty of ribosomes. A great number of Langhans' cells were noticed in early gestation; only very few were noticed the later part. Mitochondria of Langhans' cells were comparatively large and the Golgi system was well-developed in the first trimester. Endoplasmic reticulum was less well developed and there were few ribosomes. The basement tended to become thicker a pregnancy proceeded and lamellar structures appeared on its inner face.
对妊娠4周、6周、8周、10周以及足月时获取的人胎盘样本进行了透射电子显微镜（TEM）研究。妊娠早期的绒毛膜绒毛在合体滋养层的游离表面呈现出丰富的微绒毛。足月时的绒毛膜绒毛被合体滋养层覆盖，其游离表面有短微绒毛。合体细胞的密度明显高于朗汉斯细胞。在妊娠早期，在合体细胞内部发现了分裂膜。合体细胞的细胞质含有相对较小的线粒体、发育良好的内质网细胞、发育不良的高尔基体系统、电子致密的脂质小滴和大量核糖体。在妊娠早期发现大量朗汉斯细胞；后期仅发现极少数。朗汉斯细胞的线粒体相对较大，在妊娠头三个月高尔基体系统发育良好。内质网发育较差，核糖体较少。随着妊娠进展，基底膜趋于变厚，其内表面出现层状结构。
