User:Edidzba/Germinal disc

= Germinal disc = From Wikipedia, the free encyclopedia Jump to navigationJump to search Germinal disc may refer to:

In birds[edit]
The germinal disc, also called the blastodisc, is a small, circular, white spot (approximately 1.5-3 mm across) on the surface of the yellow yolk of a bird's egg.

In mammals[edit]
The blastodisc is a round single-cell layer of cells inside the blastula from which the embryo is going to form. The blastodisc is composed of two layers: hypoblast and epiblast. The hypoblast layer lies adjacent to the blastocyst cavity and is composed of small, cuboidal cells. The epiblast layer, composed of a layer of columnar cells, is adjacent to the amniotic cavity. (CITE 1)

References[edit]

 * Early Development in Fish
 * Early Development in Birds