Ultrastructure of the human ovum fertilized in vitro
Tesarík, J.; Dvorák, M.
Folia Morphologica 29(3): 297-304
1981
ISSN/ISBN: 0015-5640 PMID: 7274864 Document Number: 180282
Ultrastructure of the human fertilized 1-cell ovum obtained by in vitro insemination was studied. The initial material was the Graafian follicle oocyte cultivated 48 h in vitro prior to insemination to allow it to mature. Two pronuclei, male and female, ultrastructurally indistinguishable from each other were found in the fertilized human ovum. They were characterized by the presence of 5-8 compact nucleoli. A peripheral and a central cytoplasmic zone were differentiated according to the distribution of cytoplasmic structures. Signs of cortical reaction were found in the peripheral zone, which was relatively poor in cytoplasmic structures. Large numbers of mitochondria with a typical structure and with a very close relationship to the cisternae of the smooth endoplasmic reticulum, the annulate lamellae and the nuclear envelope were present in the central zone, where the Golgi complex, polymorphous complexes, multivesicular bodies and (very rarely) granular endoplasmic reticulum structures, and free ribosomes were also observed. Presence of glycogen is debatable. Results are discussed with reference to findings obtained in the study of mammalian ova, both unfertilized and fertilized in vivo.