Final answer:
Approximately 6 days after conception, implantation occurs, where the blastocyst attaches to the uterine lining, initiating further embryonic development and hormone release for pregnancy maintenance.
Step-by-step explanation:
Approximately 6 days after conception, implantation takes place. This is the process where the embryo, which has developed from the zygote through a series of mitotic divisions, attaches itself to the lining of the mother's uterus. During the first few days post-conception, the zygote forms into a blastocyst, consisting of about 100 cells organized around a fluid-filled cavity known as the blastocoel.
The blastocyst segregates into two key groups of cells: the inner cell mass, which will become the embryo, and the trophoblasts which form the outer layer and are responsible for developing into the chorionic sac and the fetal portion of the placenta. Upon implantation, the next stage of embryonic development begins, and the blastocyst's outer layer releases a hormone called human beta chorionic gonadotropin (ß-HCG), which is crucial for maintaining the endometrium and supporting the developing embryo.