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[blas-chuh-luh] /ˈblæs tʃə lə/
noun, plural blastulas, blastulae
[blas-chuh-lee] /ˈblæs tʃəˌli/ (Show IPA).
the early developmental stage of an animal, following the morula stage and consisting of a single, spherical layer of cells enclosing a hollow, central cavity.
Compare blastocyst.
Origin of blastula
1885-90; < New Latin < Greek blast(ós) bud, sprout + New Latin -ula -ule
Related forms
blastular, adjective
[blas-chuh-ley-shuh n] /ˌblæs tʃəˈleɪ ʃən/ (Show IPA),
noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for blastulation


(embryol) the process of blastula formation


noun (pl) -las, -lae (-liː)
an early form of an animal embryo that develops from a morula, consisting of a sphere of cells with a central cavity Also called blastosphere
Derived Forms
blastular, adjective
Word Origin
C19: New Latin; see blasto-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for blastulation



embryonic state, 1875, Modern Latin, from Greek blastos "sprout, germ" + diminutive ending -ula.

Online Etymology Dictionary, © 2010 Douglas Harper
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blastulation in Medicine

blastula blas·tu·la (blās'chə-lə)
n. pl. blas·tu·las or blas·tu·lae (-lē')
An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity.

blas'tu·lar adj.
blas'tu·la'tion (-lā'shən) n.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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blastulation in Science
Plural blastulas or blastulae (blās'chə-lē')
An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped layer of cells around a fluid-filled cavity known as a blastocoel. Compare gastrula. See also blastocyst.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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blastulation in Culture
blastula [(blas-chuh-luh)]

The stage of an embryo that consists of just over a hundred cells — a stage reached about one week after fertilization. At this stage the cells are just at the very beginning of cellular differentiation and are said to be totipotent (See totipotency).

Note: This is the stage of development where embryonic stems cells can be harvested for medical research.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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