Fig. 21. Very high power TEM of an apical tight junction in the appositional region of two trophoblast cells of a mid blastocyst, stage 3 embryo, 96-120 hours post-insemination (x103,000). Astericks indicate the boundaries of the underlying microfilaments. Inset is a low magnification showing the location of tight junctional regions between trophoblast cells (original magnification x5,000). The boxed in area is the location of the tight junctional region on the left. Astericks mark more basal tight junctional regions.
G, annular gap junction.
(From: Gualtieri, Santella, and Dale, 1992. Reproduced with permission of the publisher, John Wiley & Sons.)