An early stage of an embryo formed by the rearrangement of the blastomeres of the morula to form a hollow sphere. [G. blastos, germ]
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blas·tu·la 'blas-chə-lə n, pl -las or -lae -.lē an early metazoan embryo typically having the form of a hollow fluid-filled rounded cavity bounded by a single layer of cells compare GASTRULA, MORULA
blas·tu·lar -lər adj
blas·tu·la·tion .blas-chə-'lā-shən n
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n.
an early stage of the embryonic development of many animals. The equivalent stage in mammals (including humans) is the blastocyst.
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blas·tu·la (blasґtu-lə) pl. blasґtulae [L.] the usually spherical structure produced by cleavage of a zygote, consisting of a single layer of cells (blastoderm) surrounding a fluid-filled cavity (blastocoele); called also blastosphere. See also discoblastula. blastular adjMedical dictionary. 2011.