Fig. 36. Morphological changes that occur during hatching are: 1) the zona pellucida is shed, 2) the blastocyst expands, 3) the blastocystic cavity enlarges and the quantity of fluid increases, 4) the cells of the trophoblast and the inner cell mass continue to proliferate, 5) the mural trophoblast thins and tight junctions form between individual cells, 6) the inner cell mass begins to differentiate into epiblast and hypoblast.
(Adapted from: Veeck and Zaninovic´, 2003. Reproduced with permission of the publisher, Francis and Taylor Group.)
|