INSIDEEMBRYO · FERTILITY GLOSSARY
The zona pellucida is a specialised extracellular glycoprotein matrix surrounding the mammalian oocyte and early preimplantation embryo. In humans, its principal structural glycoproteins include ZP1, ZP2, ZP3 and ZP4. The zona contributes to oocyte protection, sperm–oocyte interaction and maintenance of…
The zona pellucida is a specialised extracellular glycoprotein matrix surrounding the mammalian oocyte and early preimplantation embryo. In humans, its principal structural glycoproteins include ZP1, ZP2, ZP3 and ZP4. The zona contributes to oocyte protection, sperm–oocyte interaction and maintenance of structural integrity during early cleavage. Following oocyte activation, cortical granule-derived modifications alter zona properties and contribute to mechanisms restricting additional sperm penetration. The zona pellucida remains around the developing embryo until blastocyst expansion and hatching occur before implantation.
For education, not individual medical advice. Ask your fertility team about your care.