High power TEM of a section of a blastomere of a stage 2, 4-cell embryo in vivo (original magnification x40,000). Blebs that protrude from the nuclear membrane (arrows) are closely related to mitochondria.
From: Pereda and Croxatto, 1992. Reproduced with permission of the Annals, Academy of Medicine, Singapore.
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Keywords: four-cell embryo, mitochondria, nuclear membrane, stage 2 embryo
Source: The Virtual Human Embryo.