Fertilization
The process Assessment IVF ICSIThe Process - sperm
capacitation hyperactivation zona binding acrosome reaction zona penetration sperm-oocyte membrane fusion sperm engulfed decondensation of sperm nucleus formation of male pronucleusThe Process - Egg
Ovulation Sperm-egg membrane fusion Egg activation increase in Ca++ cortical reaction - zona block completion of meiosis (2nd PB) formation of female pronucleus Syngamy - fusion of both pronucleiCapacitation
process of sperm becoming fertile occurs in uterus must be removed from seminal fluid in vitro, wash sperm capacitated sperm have the ability to fertilize the egg
Hyperactivation
facilitates sperm-oocyte contact occurs in oviduct motility pattern becomes frenzied linear to non-linear motionZona Binding
Zona proteins: ZP1, ZP2, ZP3 Sperm bind ZP3 specifically Initiates acrosome reactionAcrosome Reaction
Fusion of two membranes spermatazoal plasma membrane outer acrosomal membrane Acrosin released allows sperm to penetrate zona Exposes equatorial segment for fusion with eggSperm-Egg Fusion
Equatorial segment of sperm Plasma membrane of egg Initiates egg activationEgg Activation
Cortical Reaction exocytosis of cortical granules Zona block biochemical changes eliminates sperm bindingAssessment of Fertilization
Check for PN 15-18 hrs post insemination Normal Fertilization 2 PN in ooplasm 2 PB perivitelline spaceAbnormal Fertilization
> 2 PN in ooplasm polyspermic: >1 male PN, 1 female PN, 2PB polygynic: >1 female PN, 1 male PN, 1PB failure to extrude second PB Spontaneous oocyte activation 1 female PN, 2 PB Condensed sperm: 1 female PN, 2 PB Oocyte activation (digynic) >1female PN, 1 PB