A COMPARATIVE STUDY OF THE FINE STRUCTURE OF THE TROPHOBLAST IN SEVERAL HEMOCHORIAL PLACENTAS.
A COMPARATIVE STUDY OF THE FINE STRUCTURE OF THE TROPHOBLAST IN SEVERAL HEMOCHORIAL PLACENTAS.
复制标题
几种血细胞胎盘滋养细胞精细结构的比较研究。
作者：
A. Enders
用电子显微镜检查了四个目九个物种妊娠晚期胎盘迷路或绒毛的部分。在这些胎盘中发现了明显的滋养层分层模式，这些胎盘都是血绒质型的。实验室大鼠、实验室小鼠、仓鼠和鹿小鼠在母体血液空间和胎儿血管之间有三层滋养层（血绒毛膜），兔子有两层（血绒毛膜），豚鼠和花栗鼠有一层（迷路血绒毛膜），人类和犰狳有一层（绒毛血绒毛膜）。
血毛胎盘的滋养层外层（紧邻母体血液的一层）是细胞性的，但接下来的两层显然是合胞体，并且彼此紧密相连。兔胎盘的外层是合胞体，而内层则含有一些细胞袋。在所有检查的血单绒毛胎盘中，滋养层的连续层是合胞体的。研究发现，所有研究的胎盘的滋养层表面层都富含颗粒状内质网，而在后续各层中，这种元素的含量较少。所有胎盘均显示滋养层的表面和基底修饰，但发现小凹（胞饮小泡）最常见于隐窝、囊袋或其他与表面有些距离的区域。这表明母体血浆相对停滞的区域可能对于胎盘吸收某些物质很重要。
Portions of the labyrinth or villi of placentas from late pregnancy from nine species in four orders of mammals were examined with the electron microscope. Pronounced patterns of layering of the trophoblast were found in these placentas which were all of the hemochorial type. The laboratory rat, laboratory mouse, hamster, and deer mouse have three layers of trophoblast between the maternal blood space and fetal vessels (hemotrichorial), the rabbit two layers (hemodichorial), the guinea pig and chipmunk one layer (labyrinthine hemomonochorial), and the human and armadillo one layer (villous hemomonochorial).
The outer layer of trophoblast of the hemotrichorial placentas (the layer next to the maternal blood) is cellular, but the next two layers are apparently syncytial and are closely apposed to one another. The outer layer of the rabbit placenta is syncytial, while the inner layer contains some pockets of cells. In all of the hemomonochorial placentas examined, the continuous layer of trophoblast was syncytial. It was found that the surface layer of trophoblast of all the placentas studied is rich in granular endoplasmic reticulum, whereas in subsequent layers this element is less abundant. All of the placentas show both surface and basal modifications of trophoblast, but caveolae (pinocytotic vesicles) were found to be most commonly located in crypts, pockets, or other regions somewhat removed from the surface. It is suggested that an area of relative stasis of maternal plasma may be important for absorption of some substances by the placenta.