Turning of embryo from gastrula to neurula

Question

How does the embryo turn from gastrula to neurula? How is the neural tube made? What is the embryonic origin of nervous system in vertebrates?

Answer 1

The neurula phase is characterized by the appearing of neural tube all along the dorsal area of the embryo. The growing of mesoderm in that area induces the differentiation of ectodermal cells just above. Such cells then differentiate making the neural tube. Thus, the origin of nervous system is the ectoderm (the similar germ layer which gives birth to the skin).