parablastn.
/ˈparəblɑːst/, /ˈparəblast/, U.S. /ˈpɛrəˌblæst/ΚΠ
1857 R. G. Mayne Expos. Lexicon Med. Sci. (1860) Parablasta, term used by Eisenmann for disease with anatomical conversion or alteration: a parablast.
2. Embryology. Esp. in the terminology of W. His: a layer of cells that gives rise to the blood vessels and connective tissue of the embryo (embryonic mesenchyme), (supposedly) located outside the blastoderm. Now historical.
ΘΚΠ
the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [noun] > ovum or ootid > yolk > types of yolk
germ yolk1849
archiblast1876
parablast1876
tropholecithus1879
1876 E. Klein in Q. Jrnl. Microsc. Sci. 16 116 This quasi-extraneous portion of the germ I will call parablast, in contradistinction to the segmented part or blastoderm of the authors, which I will term archiblast... However,..according to His, parablast is not a portion of the same substance of which the blastoderm consists, but is a part of the white yolk.
1888 Q. Jrnl. Microsc. Sci. 29 195 There are here also plenty of mesoblast—pardon, ‘parablast’ cells in the neighbourhood.
1940 Q. Rev. Biol. 15 6/2 This theory..claimed that the archiblast..gives rise to all the embryo except the blood vessels and connective tissue which are furnished by the parablast.
1999 Isis 90 469 I will not examine his daring and controversial ‘parablast’ theory but focus on the second of the two major claims he made in a series of publications between 1866 and 1875.
This entry has been updated (OED Third Edition, June 2005; most recently modified version published online March 2022).
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n.1857