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The vitelline membrane or vitelline envelope is a structure surrounding the outer surface of the plasma membrane of an ovum (the oolemma) or, in some animals (e.g., birds), the extracellular yolk and the oolemma. It is composed mostly of protein fibers, with protein receptors needed for sperm binding which, in turn, are bound to sperm plasma ...
The insect vitelline envelope is the outer proteinaceous layer outside the oocyte and egg. The vitelline envelope, not being a cellular structure, is commonly referred to as a membrane. However, this is a technical misnomer as the structure is composed of protein and is not a cellular component. It varies in thickness between different insects ...
The vitelline membrane consists of two major layers found below the ovary and the outer layer found in the oviduct. This membrane supports the yolk and separates from the albumen , or egg white. The proteins that primarily compose the vitelline membrane are the lysozyme and ovomucin foundational for membrane growth during embryonic development.
The zona pellucida is a translucent matrix of cross-linked glycoprotein filaments that surrounds the mammalian oocyte and is 6.5–20 μm thick depending on the species. Its formation, which depends on a conserved zona pellucida-like (ZP) module that mediates the polymerization of egg coat components, [2] is critical to successful fertilization. [3]
Vitelline circulation, the system of blood flowing between an embryo and its yolk sac; Vitelline cyst, a developmental defect relating to the closure of the vitelline duct; Vitelline duct, a tube that joins the yolk sac to the midgut lumen of a human embryo; Vitelline membrane, membrane surrounding an ovum
The egg jelly is located immediately surrounding the vitelline envelope and consists primarily of a network of short peptides and sulfated fucan glycoproteins. [1] These short peptides diffuse into the surrounding area and stimulate respiration and movement of the sperm to the egg. [ 1 ]
The major role of the vitelline membrane is to prevent the mixing of the yolk and albumen and also act as an important anti-microbial barrier, as indicated by the high content of lysozyme in the outer layer [1] Vitelline membrane outer layer protein I (VMO-I) binds tightly to ovomucin fibrils, which construct the backbone of the outer layer membrane.
In the human embryo, the vitelline duct, also known as the vitellointestinal duct, [1] the yolk stalk, [1] the omphaloenteric duct, [1] or the omphalomesenteric duct, [1] is a long narrow tube that joins the yolk sac to the midgut lumen of the developing fetus. [2]