Very high power TEM of adjacent surfaces of two polar cells in a stage 2 morula in vitro (original magnification x75,500) 96-120 hours post-insemination . Notice the obliquely cut tight junction region (TJR) adjacent to a gap junction (G) at the apical level of the cells.
From: Gualtieri et al., 1992. Reproduced with permission of the publisher, John Wiley & Sons.
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Source: The Virtual Human Embryo.