from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The process of forming a gastrula.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The stage of embryo development at which a gastrula is formed from the blastula by the inward migration of cells
from the GNU version of the Collaborative International Dictionary of English
- n. The process of invagination, in embryonic development, by which a gastrula is formed.
from The Century Dictionary and Cyclopedia
- n. In embryology, the formation of a gastrula; the process whereby a germ is converted from a morula or a blastula into a gastrula.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the process in which a gastrula develops from a blastula by the inward migration of cells
It has been an old dream of mine to substitute for the presumptive mouth region of a newt the foreign ectoderm which comes from a frog early in gastrulation, since I wanted to find out what kind of
Yet in vertebrates, as the notochord is forming during a developmental process called gastrulation, it first functions to establish the midline of the embryo.
The next stage, gastrulation, is the subject of a famous bon mot by Lewis Wolpert: ‘It is not birth, marriage, or death, but gastrulation, which is truly the most important time in your life.’
The processes of cell signaling important in inducing new tissues during gastrulation are similar in all vertebrates, and the same answers are turning up in fish and mice, despite the morphological differences in their layouts.
These differences in shape lead to some apparent differences in the next step of development, gastrulation.
The critical function of gastrulation is that some cells have to move inward, into the mass of cells.
Whether the embryo is a ball of cells or a mass on top of a yolk, though, all vertebrates carry out equivalent movements during gastrulation; again, the differences are superficial, depending on whether the cluster of cells is balled up or flattened.
In neurulation, as in gastrulation, invagination is much in evidence.
Below is one of the things that sheets of cells are observed to do during the course of embryonic development, for example during gastrulation.
It was the same blastula-like starting point as we had for the model of gastrulation above.