Trophectoderm vs. Trophoblast

Trophectodermnoun

(biology) The ectoderm from which the trophoblast develops.

Trophoblastnoun

(cytology) 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.

Trophoblastnoun

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

Trophoblast

Trophoblasts (from Greek 'trephein': to feed; and 'blastos': germinator) are cells that form the outer layer of a blastocyst. They are present four days post-fertilization in humans.