(trō'fŏ-blast‵ )

[ tropho- + -blast ]

The outermost layer of the developing blastocyst. It differentiates into two layers, the cytotrophoblast and syntrophoblast.

SEE: blastocyst; cytotrophoblast; syntrophoblast; fertilization for illus.

trophoblastic,

(trō‵fŏ-blast'ik )