Endometrium with eggcell (100X)

The villi are easy to see, and they are made up of two different types of trophoblastic cells. The two kinds of cells, the cytotrophoblasts and syncytiotrophoblasts, are more clearly distinguished at a higher magnification. Between the villi you have the intervillous space where some (maternal) blood is seen. These are secondary villi (containing extraembryonic mesoderm but no vessels). Primary villi consist of trophoblasts only, while tertiary villi contain mesoderm and fetal vessels.