c Zona reaction: Cortical granules-perivitelline space degrade zp-3, alteration of zona pellucida ->barrier for sperm penetration The second meiotic division of the secondary oocyte is rapidly lifted and the second ○ polar body is released leaving a haploid female nucleus▪ The second meiotic division of the secondary oocyte is rapidly lifted and the second polar body is released, leaving a haploid female nucleus. Zona reaction: Cortical granules→perivitelline space →degrade ZP-3, alteration of zona pellucida →barrier for sperm penetration