An enlarged part of the preceding section reveals branched villi on the entire external surface of the chorion. The cytotrophoblast at the tips of the villi is in process of forming a continuous zone (Cyto.) around the embryo. Section 428.
Fig. 17. Heuser et al., 1945.
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Keywords: chorion, chorionic villi, cytotrophoblast, embryo
Source: The Virtual Human Embryo.