Embryonic disc

Embryonic disc
Section through embryonic disk of Vespertilio murinus.
Surface view of embryo of a rabbit. (After Kölliker.) arg. Embryonic disk. pr. Primitive streak.
Details
Carnegie stage	4
Identifiers
Latin	discus embryonicus
Code	TE E2.0.1.2.0.0.14
*Anatomical terminology* [edit on Wikidata]

The floor of the amniotic cavity is formed by the embryonic disc (or embryonic disk) composed of a layer of prismatic cells, the embryonic ectoderm, derived from the inner cell-mass and lying in apposition with the endoderm.

In humans, it is the stage of development that occurs after implantation and prior to the embryonic folding (e.g. seen between about day 14 to day 21 post fertilization). It is derived from the epiblast layer, which lies between the hypoblast layer and the amnion. The epiblast layer is derived from the inner cell mass. Through the process of gastrulation, the bilaminar embryonic disc becomes trilaminar. The notochord forms thereafter. Through the process of neurulation, the notochord induces the formation of the neural tube in the embryonic disc.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

Diagram at manchester.ac.uk

Human embryogenesis in the first three weeks

Week 1

Week 2
(Bilaminar)

Week 3
(Trilaminar)

Germ layers	Archenteron/Primitive streak Primitive pit Primitive knot/Blastopore Primitive groove Gastrula Gastrulation Regional specification Embryonic disc

Ectoderm	Surface ectoderm Neuroectoderm Somatopleuric mesenchyme Neurulation Neural crest

Endoderm	Splanchnopleuric mesenchyme

Mesoderm	Axial mesoderm Paraxial Somite Somitomere Intermediate Lateral plate Intraembryonic coelom Splanchnopleuric mesenchyme Somatopleuric mesenchyme

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