Zona (redirected from zona perforata)

Zo´na

n.

1.

A zone or band; a layer.

Zona pellucida
a -	(Biol.) The outer transparent layer, or envelope, of the ovum. It is a more or less elastic membrane with radiating striæ, and corresponds to the cell wall of an ordinary cell. See Ovum, and Illust. of Microscope.
b -	The zona radiata.

Zona radiata

(Biol.) a radiately striated membrane situated next the yolk of an ovum, or separated from it by a very delicate membrane only.

Thesaurus

Noun

1.

zona - (anatomy) any encircling or beltlike structure zone anatomical structure, bodily structure, body structure, complex body part, structure - a particular complex anatomical part of a living thing; "he has good bone structure" zona pellucida - 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 zonula, zonule - small beltlike zone anatomy, general anatomy - the branch of morphology that deals with the structure of animals