Science / Biology / Blastocyst: The developmental stage of the fertilized ovum by the time it is ready to implant; formed from the morula and consists of an inner cell mass, an internal cavity, and an outer layer of cells (the trophoblast).
Science / Biology / Trophoblast: The outer layer of cells of a blastocyst that adhere to the endometrium during implantation. MORE
Science / Biology / Implantation: The process in which the blastocyst embeds in the endometrium. MORE