Fig. 16. Close-up view of a stage 3 embryo in vitro showing a schematic of trophoblast cell junctions. Extremely close connections called tight junctions are formed between the membranes of trophoblastic cells. Disk-shaped junctions called desmosomes also form between trophoblast cell membranes.
(From: Veeck and Zaninovic´, 2003. Reproduced with permission of the publisher, Francis and Taylor Group.)