Vitelline membrane

Vitelline membrane

Infobox Embryology
Name = Vitelline membrane
Latin = m. vitellina
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The vitelline membrane is a structure directly adjacent to the outer surface of the plasma membrane of an ovum. It is composed mostly of protein fibers, with protein receptors needed for sperm binding, binding to sperm plasma membrane receptors. The species-specificity between these receptors contributes to prevention of breeding between different species.

It is called zona pellucida in mammals.

As soon as the spermatozoon fuses with the ovum, signal transduction occurs, resulting in an increase of cytoplasmic calcium ions. This itself triggers the cortical reaction, which results in depositing several substances onto the vitelline membrane through exocytosis of the cortical granules, transforming it into a hard layer called the “fertilization membrane”, which serves as a barrier inaccessible to other spermatozoa. This phenomenon is the slow block to polyspermy.

ee also

* Zona pellucida
* Egg activation
* Cortical reaction


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Look at other dictionaries:

  • vitelline membrane — n a membrane enclosing the egg proper and corresponding to the plasma membrane of an ordinary cell * * * the cytoplasmic, noncellular membrane surrounding an oocyte …   Medical dictionary

  • vitelline membrane — noun Date: 1845 a membrane enclosing an egg that comprises the zona pellucida in mammals and that upon fertilization splits off from the surface of the egg forming a fertilization membrane in many invertebrates and amphibians and in some fish …   New Collegiate Dictionary

  • vitelline membrane — a membrane, product of the ooplasmic surface which adheres closely to the outer boundary of the ooplasm, but as fertilization separates from the surface as a distinct membrane …   Dictionary of ichthyology

  • vitelline membrane — noun : a membrane enclosing the egg proper and corresponding to the cell wall of an ordinary cell; especially : a membrane separated from the surface of the egg in many invertebrates immediately the egg is fertilized, thus preventing other… …   Useful english dictionary

  • vitelline membrane — A membrane enclosing eggs of invertebrates located within an egg shell …   Dictionary of invertebrate zoology

  • vitelline membrane — The membrane, usually of protein fibres, immediately outside the plasmalemma of the ovum and the earlier stages of the developing embryo. Its structure and composition vary in differing animal groups …   Dictionary of molecular biology

  • vitelline membrane — the membrane surrounding the egg yolk. [1835 45] * * * …   Universalium

  • vitelline membrane — noun Embryology a transparent membrane surrounding and secreted by the fertilized ovum, preventing the entry of further spermatozoa …   English new terms dictionary

  • vitelline membrane — vitel′line mem′brane n. cbl the membrane surrounding an egg yolk • Etymology: 1835–45 …   From formal English to slang

  • vitelline membrane — /vəˈtɛlən mɛmbreɪn/ (say vuh teluhn membrayn) noun the membrane surrounding the egg yolk …  

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