trophoblast

The outermost layer of cells of the mammalian blastocyst that attaches the fertilized ovum to the uterine wall and serves as a nutritive pathway for the embryo.

An external epiblastic layer that does not enter into the formation of the embryo, but does take an active part in nutritional processes intended for it; the blastocystic ectoderm.

The membrane of cells that forms the wall of a blastocyst during early pregnancy, providing nutrients to the embryo and later developing into part of the placenta.

the membrane that forms the wall of the blastocyst in early development; aids implantation in the uterine wall