| 释义 |
gastrula
gas·tru·la G0056900 (găs′trə-lə)n. pl. gas·tru·las or gas·tru·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.
[New Latin : Greek gastēr, gastr-, belly + Latin -ula, feminine diminutive suff.]
gas′tru·lar (-lər) adj.gastrula (ˈɡæstrʊlə) n, pl -las or -lae (-ˌliː) (Biology) a saclike animal embryo consisting of three layers of cells (ectoderm, mesoderm, and endoderm) surrounding a central cavity (archenteron) with a small opening (blastopore) to the exterior. See also ectoderm, mesoderm, endoderm[C19: New Latin: little stomach, from Greek gastēr belly] ˈgastrular adjgas•tru•la (ˈgæs trʊ lə)
n., pl. -las, -lae (-ˌli) an embryo in an early stage of development during which the blastula differentiates into two cell layers and the central cavity becomes the archenteron. [1875–80] gas′tru•lar, adj. gas`tru•la′tion, n. gas·tru·la (găs′trə-lə) Plural gastrulas or gastrulae (găs′trə-lē′) An embryo at the stage following the blastula, in which the cells are distributed into layers that eventually develop into the organs of the body. Compare blastula.Thesaurus| Noun | 1. |  gastrula - double-walled stage of the embryo resulting from invagination of the blastula; the outer layer of cells is the ectoderm and the inner layer differentiates into the mesoderm and endodermconceptus, fertilized egg, embryo - an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval lifearchenteron - central cavity of the gastrula; becomes the intestinal or digestive cavity |
TranslationsGastrula
gastrula[′ga·strə·lə] (embryology) The stage of development in animals in which the endoderm is formed and invagination of the blastula has occurred. Gastrula one of the stages of embryonic development in multicellular animals. In the gastrula stage the embryo has a two-layer wall and cavity (gastrocoel) that communicates with the surrounding environment by means of an opening, the blastopore. The outer wall is called the ectoderm; the inner wall, the endoderm. They are the primordial embryonic layers. In the beginning the endoderm, and less frequently the ectoderm, also contains the material for a middle layer of tissue—the mesoderm. At the end of gastrulation, the mesoderm separates and becomes independent, and the embryo is transformed from a two-layer to a three-layer organization. The transformation from the blastula to the gastrula takes place differently in different animals. Already at the gastrula stage, certain differences in the properties of the embryonic layers that are precursors of their morphological differentiation can be observed. The differences in structure of the embryos of different animals at this stage of development are determined both by the structure of the eggs and by the different modes of existence of the embryos. In most animals the embryo spends the gastrula stage in the egg envelope or in the mother’s body; in some hydrozoans the gastrula is a free-living larva. Sometimes the differences pertain to the most general features; for example, in the embryos of bony fish the gastrocoel is lacking, and in certain coelenterate gastrulae the blastopore is lacking. The presence of the gastrula stage (with its characteristic separation into embryonic tissues) in the development of all multicellular organisms was demonstrated by A. O. Kovalevskii and E. Metchnikoff and provided proof of the common origin of animals. T. A. DETLAF gastrula
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 (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]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
Words related to gastrulanoun double-walled stage of the embryo resulting from invagination of the blastulaRelated Words- conceptus
- fertilized egg
- embryo
- archenteron
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