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Medical Term:


Pronunciation: blas′tō-derm, -tō-der′ma


The thin, disc-shaped cell mass of a young embryo and its extraembryonic extensions over the surface of the yolk; when fully formed, all three primary germ layers (ectoderm, endoderm, and mesoderm) are present.

Synonym(s): germ membrane, germinal membrane, membrana germinativa

[blasto- + G. derma, skin]

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.