Both epidermis and neural plate are capable of giving rise to neural crest cells . The notochord is necessary in order to induce neural plate formation. Phelps Below are scanning electron micrographs of a chick embryo during neurulation. During neurulation, somites form in pairs flanking the neural tube. Somites are blocks of cells that form a segmental pattern in the vertebrate embryo.
Somites produce cells that become vertebrae, ribs, muscles, and skin.
The region where neural tube closure begins varies between different classes of vertebrates. In amphibians such as Xenopus , the neural tube closes almost simultaneously along its entire length. In birds , the neural tube closes in the anterior to posterior direction, as Hensen's node regresses. Mammalian neurulation is similar to that of birds, however the bulky anterior neural plate seems to resist closure - the middle of the tube closes first, followed by both ends. You should recognize the beginning of the film from our discussion of gastrulation.