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

Pronuclear nucleolus

Pronuclear nucleolus

High power TEM of part of a pronuclear nucleolus in a stage 1b embryo in vitro, 17 hours post-insemination (original magnification x51,710). The nucleolus is dense, compact and homogenous, and composed of fine fibrils. The chromatin is highly dispersed and finely granular.

From: Sathananthan and Trounson, 1985. Reproduced with permission of the publisher, John Wiley & Sons.


Keywords: chromatin, nucleolus, pronuclear nucleolus, stage 1b embryo


Source: The Virtual Human Embryo.