Skip Navigation
Stage 1 / 1 day Stage 2 / 2-3 days Stage 3-1 / 4 days Stage 3-2 / 4-5 days Stage 4 / 6 days Stage 5a-1 / 7 days Stage 5a-2 / 8 days Stage 5b / 9 days Stage 5c / 12 days Stage 6 / 13-17 days Stage 7 / 16-19 days Stage 8 / 23 days Stage 9 / 25 days Stage 10 / 28 days Stage 11 / 29 days Stage 12 / 30 days Stage 13 / 32 days Stage 14 / 33 days Stage 15 / 36 days Stage 16 / 39 days Stage 17 / 41 days Stage 18 / 44 days Stage 19 / 45-47 days Stage 20 / 49 days Stage 21 / 49-52 days Stage 22 / 52-55 days Stage 23 / 56 days
Carnegie Stage   Figure

Nucleus and surrounding cytoplasm of a 2-cell embryo

Nucleus and surrounding cytoplasm of a 2-cell embryo

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.

Click on the picture to view the full-sized image.


Keywords: Golgi complex, blastomere, chromatin, cytoplasm, heterochromatin, lipofuscin, mitochondria, multivesicular body, nucleus, smooth endoplasmic reticulum, stage 2 embryo, two-cell embryo, vacuole(s), vesicles


Source: The Virtual Human Embryo.