While this is happening, the is secreting proteolytic enzymes to burrow into the ?

While this is happening, the trophoblast is secreting proteolytic enzymes to burrow into the endometrium. Trophoblast are the peripheral cells of the blastocyst, which normally attach the fertilized egg to the uterine wall thus contributes to the placenta and the membranes that nourish and protect the developing zygote.