embryonic disk

American  

[em-bree-on-ik disk] / ˈɛm briˌɒn ɪk ˈdɪsk /

noun

Embryology.

1. Also called embryonic shield.  in the early embryo of mammals, the flattened inner cell mass that arises at the end of the blastocyst stage and from which the embryo begins to differentiate.

2. the blastodisk of yolky eggs.

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Etymology

Origin of embryonic disk

First recorded in 1935–40

Example Sentences

Roughly two weeks after fertilization, more than half of the embryos had an embryonic disk — a flat mass of cells.

From Scientific American

When the mesoblast has become thus infinitely subdivided into hundreds of minute spheres, the ectoblast bursts, and the new generations of cells thus set free collect in that part of the egg where the embryonic disk is to arise.

From Project Gutenberg

He first solved the difficult problem of the transformation of this four-fold, flat, leaf-shaped, embryonic disk into the complete vertebrate body, through the conversion of the layers or plates into tubes.

From Project Gutenberg

The large round food-yelk of the bird's egg causes, in the first place, a flat discoid expansion of the small gastrula, and then so distinctive a development of this thin round embryonic disk that the controversy as to its significance occupies a large part of embryological literature.

From Project Gutenberg

At the beginning of germination the flat embryonic disk curves outwards, and separates on the inner side from the underlying large yelk-ball.

From Project Gutenberg