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Carnegie Stage   Figure

Hatching point

Hatching point

High power TEM of a hatching stage 3 embryo in vitro showing the hatching point (original magnification x5,100). Notice the zona-breaker cells (ZBC) on either side of the opening (O) in the zona pellucida (ZP) and dark tonofilaments (arrow) in the bend of one of the cells.

BC = blastocystic cavity (blastocoele)

From: Sathananthan et al., 2003. Printed from Reproductive Biomedicine Online.


Keywords: blastocystic cavity (blastocoele), hatching point, tonofilaments, zona breaker cells, zona opening, zona pellucida


Source: The Virtual Human Embryo.