[Electron microscopic studies on the preimplantation rabbit blastocyst in its interaction to the uterine environment].

Ultrastructure of the preimplantation rabbit blastocyst was studied in view of its ability to resorbe substances from the uterine environment resp. to transport them to the blastocoelic cave. The architecture of the blastocyst covering, the cell-to-cell contacts of the trophoblast and entoderm, and the unusual protuberance vesicles in the trophoblast are discussed concerning their possibly function.