gastrula

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gastrula

 [gas´troo-lah]
an embryo in the stage following the blastula stage; the simplest type consists of two layers of cells, the ectoderm and entoderm, which have invaginated to form the archenteron and an opening, the blastopore.

gas·tru·la

(gas'trū-lă),
The embryo in the stage of development following the blastula or blastocyst; in lower forms with minimal yolk, it is a simple double-layered structure consisting of ectoderm and endoderm enclosing the archenteron, which opens to the outside by way of the blastopore; in forms with considerable yolk, the configuration of the gastrula is greatly modified owing to the persistence of the yolk throughout the gastrulation process. In human embryos, the gastrula stage occurs in the third week as the embryonic disk becomes trilaminar.
Synonym(s): invaginate planula
[Mod. L. dim. of G. gastēr, belly]

gastrula

/gas·tru·la/ (gas´troo-lah) the embryo in the stage following the blastula or blastocyst; the simplest type consists of two layers of cells, the ectoderm and endoderm, which have invaginated to form the archenteron and an opening, the blastopore. In human embryos the gastrula stage occurs during the third week, as the embryonic disc becomes trilaminar, establishing the ectoderm, mesoderm, and endoderm.

gastrula

(găs′trə-lə)
n. pl. gastru·las or gastru·lae (-lē′)
An embryo at the stage following the blastula, after the movement of cells results in the formation of the three germ layers, ectoderm, mesoderm, and endoderm.

gas′tru·lar (-lər) adj.

gastrula

[gas′troo͡lə]
Etymology: Gk, gaster, stomach
the early embryonic stage formed by the invagination of the blastula. The cup-shaped gastrula consists of an outer layer of ectoderm and an inner layer of mesentoderm that subsequently differentiate into the mesoderm and endoderm. See also blastula, embryonic layer.

gas·tru·la

(gas'trū-lă)
The embryo in the stage of development following the blastula or blastocyst formation; in the human embryo, the absence of yolk allows for a rapid, direct "putting in place" of the germ layers (ectoderm and endoderm), which are derived from the pluripotential embryonic disc.
[Mod. L. dim. of G. gastēr, belly]

gastrula

The stage in the development of an EMBRYO following the BLASTULA stage when the ECTODERM, ENDODERM and primitive GUT have developed.

gastrula

a stage in embryonic development in which the BLASTULA has invaginated, so giving rise to a two-layered embryo by a process of gastrulation. see ARCHENTERON.

gastrula

an embryo in the stage following the blastula stage; the simplest type consists of two layers of cells, the ectoderm and entoderm, which have invaginated to form the archenteron and an opening, the blastopore.
References in periodicals archive ?
californica gastrulae per slide were needed to obtain at least 10 single nuclei not associated with any cellular debris or at least 10 well-spaced metaphase chromosome spreads.
cidaris), pits on the ectoderm of gastrulae, a mouth that opens late in the two-arm pluteus stage, and juvenile spine morphology.
If this interpretation is correct, then among the planktotrophic species, large egg size, apical tuft, and opaque, elongate gastrulae may represent the more primitive condition (Fig.
Gastrulae had the highest observed proportion of ribosomes in polysomes, at 75% (Table 1).
A similar set of calculations for gastrulae that have 75% of their ribosomes in polysomes (i.
The embryonic stages at which these decreases in survivorship occurred corresponded to stages associated with gastrulation, as evidenced by invaginating embryos and gastrulae (Fig.
After hatching, gastrulae developed into three types of larvae, distinguishable by their morphology (Table 1).
Previous work in our laboratory measured the amino acid composition of protein in eggs, blastulae, gastrulae, and early larval stages of S.
The physiologically active fraction of the sodium pump accounted for 12% of metabolism in blastulae and gastrulae.
The four asteroids with very large eggs start swimming nearly 20 h later than the slowest asteroid with eggs less than 250 [micro]m in diameter, and they start to swim as gastrulae rather than as blastulae.