Question

Which layer of the trophoblast is multinucleated and formed by fusion of cells?

Options

• Cytotrophoblast

• Blastocoel layer

• Inner cell mass

• Syncytiotrophoblast

Answer 1

The syncytiotrophoblast is the outer layer of the trophoblast that consists of multinucleated cells formed by fusion of individual cells. This layer is highly invasive and secretes lytic enzymes to erode the endometrium, creating a burrow for the embryo to embed itself. It forms a syncytium—a layer of protoplasm with many nuclei.