zona pellucida
Pronunciation: ZOH-nah peh-LOO-see-dah
Also written as: ZP — Zona Pellucida
Glycoprotein shell surrounding mammalian eggs that sperm must penetrate for fertilization.
Full Definition
The zona pellucida is a transparent, acellular glycoprotein matrix that surrounds the mammalian oocyte and early embryo. This structure plays crucial roles in fertilization, including species-specific sperm binding, prevention of polyspermy (fertilization by multiple sperm), and protection of the developing embryo during early cleavage divisions. In assisted reproductive technology, the zona pellucida is relevant for several procedures: intracytoplasmic sperm injection bypasses this barrier, assisted hatching may involve zona manipulation, and zona hardening can occur with maternal age or laboratory culture conditions. The embryo naturally hatches from the zona pellucida at the blastocyst stage before implantation.
Usage
Usage note: Latin terminology requiring careful pronunciation. ZP abbreviation common in embryology contexts.
In Context
- "The zona pellucida appeared thickened, necessitating assisted hatching before transfer." — Embryology report
- "Sperm-zona pellucida binding is essential for normal fertilization processes." — Research paper