14. How does the embryoturn
from gastrula intoneurula?
How is the neural tube
formed? What is the
embryonic origin of the
nervous system in
vertebrates?

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The neurula stage is by
the appearance of neural tube along
the region of the embryo.
growth of mesoderm in region
induces the differentiation ectodermal
cells just above. cellsthen
differentiate forming the tube. So
the origin the nervous system isthe
(the same germ layer
gives birth to the ).