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]

Farlex Partner Medical Dictionary © Farlex 2012

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.

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]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

gastrula

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

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

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.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

References in periodicals archive ?

jacobvi (Young et al., 1989) and seen in the gastrulae of C.

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.

Larval development and metamorphosis of the deep-sea Cidaroid urchin Cidaris blakei

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.e., 2.1 X [10.sup.10]active ribosomes per individual) yielded a higher protein synthesis rate of 6.5 ng protein embryo [sup.-1]h [sup.-1].

Ribosomal analysis of rapid rates of protein synthesis in the Antarctic sea urchin Sterechinus neumayeri

The embryonic stages at which these decreases in survivorship occurred corresponded to stages associated with gastrulation, as evidenced by invaginating embryos and gastrulae (Fig.

Elevated temperature affects development, survivorship, and settlement of the elkhorn coral, Acropora palmata (Lamarck 1816)

After hatching, gastrulae developed into three types of larvae, distinguishable by their morphology (Table 1).

Morphology and gene analysis of hybrids between two congeneric sea stars with different modes of development

Detailed studies of rates and costs of protein synthesis in blastulae, gastrulae, and larvae were undertaken for several different-aged stages of development and cohorts of such stages spawned from different adults.

Costs of protein synthesis were further examined in cohorts of gastrulae of different ages and parents from those used to test the potential concentration dependency of anisomycin on costs of protein synthesis (Fig.

Previous work in our laboratory measured the amino acid composition of protein in eggs, blastulae, gastrulae, and early larval stages of S.

Gastrulae, for instance, had a very high (~7% [h.sup.-1]) fractional rate of protein synthesis (Table 2).

The physiologically active fraction of the sodium pump accounted for 12% of metabolism in blastulae and gastrulae. This fraction of metabolism increased to 20% for early larval stages and was the dominant energy-requiring process in later larval stages, when the physiologically active fraction of this single enzyme accounted for 84% of total metabolic energy (Leong and Manahan, 1999).

Cost of protein synthesis and energy allocation during development of Antarctic sea urchin embryos and larvae

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.