from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The thick, solid, transparent outer membrane of a developed mammalian ovum. Also called oolemma.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A glycoprotein membrane surrounding the plasma membrane of an oocyte
from the GNU version of the Collaborative International Dictionary of English
- n. The zona radiata.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. thick membrane around the mammalian ovum; can be penetrated by one sperm in the fertilization process; usually remains around the fertilized egg until it is implanted in the wall of the uterus
In IVF, the outer membrane of the egg the zona pellucida is an efficient barrier in preventing the penetration of sperm that have DNA damage.
As it slowly travels the length of the tube it continues to divide but still remains cloistered within the zona pellucida, the hard outer covering or “shell” of your original egg.
By the aid of the microscope we find that these ova are composed of granular substance, in which is found a miniature yolk surrounded by a transparent membrane called the zona pellucida.
Structure of the Ovum (continue) • A distinct perivitelline space is seen between the cell membrane (vitelline membrane) and the zona pellucida.
The process involves injecting the bar codes, made from silicon, in the perivitelline space of embryos, the space between an embryo's cell membrane and its protective outer cover, known as the zona pellucida.
Enzymes present in the acrosomal granule must be released to facilitate sperm penetration through the zona pellucida.
Fifty feet away, for the second time this year, an embryologist rinses Imogene’s eggs and weakens the zona pellucida and injects one good sperm into each one.
Special enzymes in the head of the sperm help in penetrating the zona pellucida, the egg’s hard outer shell.