What is the function of zona pellucida?: (A) Prevent wrong implantation of embryo, (B) Formation of blastocyst, (C) Prevention of multiple sperm entry, (D) Prevent wrong attachment of sperm
Answer is C. Ans. C. Prevention of multiple sperm entry* Zona pellucida is a glycoprotein layer surrounding the membrane of oocytes.* Once sperms reach ova, there is release of hyaluronidase - penetration of corona radiata and cumulus cells by sperm.* Glycoproteins on the outer surface of the sperm then bind with glycoproteins on the zona pellucida of the ovum.* Zona reaction: Once sperm penetrates zona pellucida, the ovum become impermeable to other sperms, this prevents polyspermy.