Fig. 54. High power TEM of the nucleus and surrounding cytoplasm of a blastomere of a stage 2, 2-cell embryo in vitro 32 hours post-insemination (original magnification x8,400). The spherical nucleus contains a dense nucleolus composed of fine fibrils. The chromatin is dispersed and specks of heterochromatin are present. The cytoplasm contains a Golgi complex (G), mitochondria (M), vesicular endoplasmic reticulum (S) and vacuoles (V). A lipofuscin-like, multivesicular body (LB) with lipid inclusions is adjacent to the right side of the nucleus. Some smooth endoplasmic reticulum vesicles are dilated and translucent. Progressive dilation of the vesicles will give rise to vacuoles.
(From: Sathananthan, 1984. Reproduced with permission of the publisher, Elsevier.)
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