Cotyledon

This article deals with the cotyledons of animals, for the cotyledons of plants see cotyledons .

In the developmental biology of tissue animals , the term cotyledon is the first differentiation of an embryo into different cell layers , from which different structures, tissues and organs subsequently develop. The cotyledons arise from the blastula during gastrulation .

The bilaterally symmetrical animals are triploblastic ; That is, they form three cotyledons:

• Endoderm , Syn. Endoderm (inner layer)
• Mesoderm (middle layer)
• Ectoderm (outer layer)

The diploblastic trunks of the cnidarians and comb jellyfish form only two cotyledons .

The transformation of cells from one cotyledon into cells of another is called transdifferentiation .

literature

• Cleveland P. Hickman, Allan Larson, Larry S. Roberts, David J. Eisenhour: Zoology . Pearson Germany, Hallbergmoos 2008, ISBN 978-3-8273-7265-9 , pp. 245-246 .