Definition of Zona pellucida
Zona pellucida: The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg's travel through the fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the zona pellucida disappears, to permit implantation in the uterus.
Source: MedTerms™ Medical Dictionaryhttp://www.medterms.com/script/main/art.asp?articlekey=11822
Last Editorial Review: 3/19/2012
Drug Medical Dictionary of Terms by Letter
Medical Dictionary Term:
Women's Health
Find out what women really need.
Updated & New
