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

Sole-shaped embryonic disk of the chick, in three successive stages of development, looked at from the dorsal surface, magnified about twenty times, somewhat diagrammatic.

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

We may now disregard both the outer ovolemma and the greater part of the vesicle, and concentrate our attention on the germinative area and the four-layered embryonic disk.

From Project Gutenberg