Processes of fertilization Corona radiata cells Phase i Phase1 Penetration of the corona radiata Polar body (放射冠), acrosomal release ● Phase ii Acrosom nner acrosomal Penetration of the zona pellucid(scm Secondary oocyte in 2nd meiotic 透明带) division ZP with receptors -zona pellucida Fusion oocyte and sperm cell membranes spongy- the release of local enzymes ● Phase iit Entrance, formation of zygoteProcesses of fertilization: •Phase I –Penetration of the corona radiata （放射冠）, acrosomal release •Phase II –Penetration of the zona pellucide（ 透明带） –ZP with receptors – zona pellucida spongy – the release of local enzymes •Phase III –Entrance, formation of zygote