Vitelline membrane

Vitelline membrane
Details
Identifiers
Latin	membrana vitellina
MeSH	A16.631.886
*Anatomical terminology* [edit on Wikidata]

The vitelline membrane is a structure surrounding the outer surface of the plasma membrane of an ovum. It is composed mostly of protein fibers, with protein receptors needed for sperm binding which, in turn, are bound 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.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

Human embryogenesis in the first three weeks

Week 1

Week 2
(Bilaminar)

Week 3
(Trilaminar)

Germ layers	Archenteron/Primitive streak Primitive pit Primitive knot/Blastopore Primitive groove Gastrula Gastrulation Regional specification Embryonic disc

Ectoderm	Surface ectoderm Neuroectoderm Somatopleuric mesenchyme Neurulation Neural crest

Endoderm	Splanchnopleuric mesenchyme

Mesoderm	Axial mesoderm Paraxial Somite Somitomere Intermediate Lateral plate Intraembryonic coelom Splanchnopleuric mesenchyme Somatopleuric mesenchyme

This article is issued from Wikipedia - version of the 1/26/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.

Vitelline membrane

See also

References