Male pronucleusZona reaction0000-L05000BA000FemalepronucleusAAUiDCPhase4Formationandfusionofpronuclei
2.1.4ImportanteventsinfertiliationBefore:>Capacitation>Acrosomereaction:releaseofenzymesfromacrosomeinducedby,andneededforspermpenetration of,the zona pellucida.During:>Penetration of coronaradiata,zona pellucidaoocyte cell membrane.>Recognition:azonaproteinZP3isresponsibleforspecies-specificfertilization
•Before: Capacitation Acrosome reaction: release of enzymes from acrosome induced by, and needed for sperm penetration of, the zona pellucida. 2.1.4 Important events in fertiliation •During: Penetration of corona radiata, zona pellucida, oocyte cell membrane. Recognition: a zona protein ZP3 is responsible for species-specific fertilization
Afterentry:>Zona reaction:zona becomes impenetrabletoothersperm(monospermy),throughenzymereleasefromcortical granules of oocytetochangestructureandcompositionofthezona>Oocytefinishes2ndmeiosis>Formation andmergeof male andfemalepronuclei
Zona reaction: zona becomes impenetrable to other sperm (monospermy), through enzyme release from cortical granules of oocyte to change structure and composition of the zona. Oocyte finishes 2nd meiosis. Formation and merge of male and female pronuclei. •After entry:
2.1.5RequirementsNormal number and viability of male andfemalegametes(sperm > 2 0 millin/ml,abnormal <20%, viability >70%)：Trinucleated oocytePrimordial follicle withtwooocytesNorrmal transport of gametes (occludedoviduct)Two gametes meet in due time
2.1.5 Requirements •Normal number and viability of male and female gametes (sperm ﹥ 2 0 millin/ml, abnormal﹤20%, viability ﹥70%) •Two gametes meet in due time. •Norrmal transport of gametes (occluded oviduct)
2.1.6SignificanceRestoration of the diploid number ofchromosomes.Determination of sex:X+X-Y+XActivation of egg and initiation of cleavage
2.1.6 Significance •Restoration of the diploid number of chromosomes. •Determination of sex: X+X→ •Activation of egg and initiation of cleavage. Y+X →