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

Pronuclei in close proximity

Pronuclei in close proximity

TEM of a stage 1b embryo in vivo near the end of the pronuclear period when the pronuclei lie in close proximity. The embryo was flushed from the uterine tube 26 hours after reported copulation and at an unknown interval after ovulation. The pronuclear plasma is highly hydrated and consists of finely dispersed granular material. The number of nucleoli increases with age. A few annulate lamellae (AL) are evident inside the pronuclei.

From: Zamboni, 1971. Reproduced with permission of the publisher, Lippincott, Williams, & Wilkins.


Keywords: annulate lamellae, nucleolus, pronuclear plasma, pronucleus, stage 1b embryo


Source: The Virtual Human Embryo.