The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. The ectoderm, like the other two layers, forms at the gastrulation stage in embryonic development (when the digestive system is developing). It forms from the epiblast .
In vertebrates, the ectoderm can be distinguished as three parts, each giving rise to different tissues:
- Cells of the neural crest
See also: neurulation.
Last updated: 10-29-2005 02:13:46