What's the noun for trophectodermal? Here's the word you're looking for.
trophoblast
(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.
“In the mammalian embryo, for instance, the first compaction of the blastomeres is under the influence of E-cadherin to produce the trophectoderm.”
“The cells lying between the primitive endoderm and the polar trophectoderm comprise the embryonic ectoderm or epiblast.”
“He created mouse embryos with DNA lacking in CDX2, the gene responsible for forming the trophectoderm, or skin on a blastocyte, which is the early form of an embryo.”