Question

After adhesion to the endometrium, the trophoblast differentiates into which two layers?

Options

• Inner cell mass (outer) and blastocoel (inner)

• Syncytiotrophoblast (outer) and cytotrophoblast (inner)

• Zona pellucida (outer) and trophoblast (inner)

• Blastomeres (outer) and morula (inner)

Answer 1

After adhesion to the endometrium, the trophoblast differentiates into two distinct layers: the syncytiotrophoblast forms the outer layer (consisting of multinucleated cells formed by fusion), and the cytotrophoblast forms the inner layer (consisting of individual cells with preserved cell boundaries). These two layers work together to facilitate implantation.