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 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.
U.S. National Library of Medicine
The plasma membrane of the egg.
The numerical value of vitelline membrane in Chaldean Numerology is: 7
The numerical value of vitelline membrane in Pythagorean Numerology is: 8
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"vitelline membrane." Definitions.net. STANDS4 LLC, 2017. Web. 28 Apr. 2017. <http://www.definitions.net/definition/vitelline membrane>.