Luckett W P
Am J Anat. 1975 Oct;144(2):149-67. doi: 10.1002/aja.1001440204.
Re-examination of early rhesus monkey and human embryos in the collection of the Carnegie Institution of Washington suggests that the mechanism of amniogenesis in both is basically similar to that of the hedgehog and vespertilionid bats. A primordial amniotic cavity develops by cavitation within the embryonic mass of 10-day rhesus monkey, and 7-day human, blastocysts. This primordial cavity has no relationship initially with the overlying trophoblast, contrary to earlier reports. Subsequently, there is a thinning and peripheral spreading of the epiblastic roof of the primordial cavity, resulting in partial opening of the roof and formation of a slightly cupped embryonic disc. The resulting space is not homologous with the primordial amniotic cavity; instead, it is a transitory tropho-epiblastic cavity. The definitive amniotic epithelium forms by the upfolding and mitotic proliferation of the margins of the epiblastic disc; this process is completed in 11-day rhesus, and 9-day human, blastocysts. Amniogenesis by cavitation is associated with the persistence of polar trophoblast following implantation, and it is suggested that this cavitation process may be essential for providing a free epithelial surface for the morphogenetic movement of epiblastic cells during subsequent formation of the primitive streak.
对华盛顿卡内基研究所收藏的早期恒河猴和人类胚胎进行重新检查表明，两者的羊膜形成机制与刺猬和蝙蝠的基本相似。在10日龄恒河猴胚胎和7日龄人类囊胚的胚胎团块内，通过空化作用形成一个原始羊膜腔。与早期报告相反，这个原始腔最初与覆盖其上的滋养层没有关系。随后，原始腔的外胚层顶变薄并向周边扩展，导致顶部分开并形成一个略呈杯状的胚胎盘。形成的空间与原始羊膜腔不同源；相反，它是一个暂时的滋养外胚层腔。确定的羊膜上皮由外胚层盘边缘的向上折叠和有丝分裂增殖形成；这个过程在11日龄恒河猴和9日龄人类囊胚中完成。通过空化作用进行的羊膜形成与植入后极滋养层的持续存在有关，并且有人认为这个空化过程对于在随后原条形成过程中为外胚层细胞的形态发生运动提供一个自由上皮表面可能是必不可少的。
