The neurulation is a stage of the embryonic Développement of the triblastic Métazoaire S during which is set up the central nervous system. It succeeds the Gastrulation. The neurulation is held in 2 stages: the primary neurulation and the secondary neurulation. The primary neurulation comprises: - the neuralisation: appearance of the plate neurale by shaping of neuroépithélium - curve and invagination - fusion of the pads and closing of the tube neural - migration The secondary neurulation is caudal.
At the Chordés, the central nervous system is dorsal compared to the digestive Tract and with the chorde. The dorsal area of the ectoderm thickens to form the plate neurale and is closed again in gutter to form a tube at the origin of brain and spinal-cord. The cells at the border between the plate neurale and the remainder of the ectoderm give rise to the cells of the Crête neurale which are at the origin of the peripheral nervous system (and of the Mélanocyte S).
At the Invertebrate S, the central nervous system is ventral compared to the digestive tract (except in the head). It is made of a series of ganglia connected by connective highly-strung persons. The neurulation was especially studied in the Drosophila. Groups of isolated cells are detached from the Ectoderme and give rise to the ganglia.
Related articles
External bonds
| Random links: | Blaise, the masked chick | Cantù | Officer of the public ministry | Arctogadus | Gary Gilmore |