BIOL 104 Lecture Notes - Lecture 9: Neural Plate, Endoderm, Neural Tube
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Your embryo becomes multilayered: ectoderm (outer layer) epidermis and nervous system, mesoderm (middle layer) bone and muscles, endoderm (inner layer) digestive and respiratory systems. The e(cid:272)toder(cid:373) (cid:271)e(cid:272)o(cid:373)es two pri(cid:373)ary (cid:862)thi(cid:374)gs(cid:863: will become the epidermis (outer layer of skin, will become the nervous system. The notochord induces the formation of the neural plate: this is the neural plate, noto(cid:272)hord se(cid:272)retes sig(cid:374)als to the e(cid:272)toder(cid:373) a(cid:374)d (cid:862)tells(cid:863) it to (cid:271)e(cid:272)o(cid:373)es (cid:374)eural tissue. The neural plate folds up into a neural tube. Neural tube closure occurs in head and tail directions: this is completed around the first month. Neurulation: the process of folding of the neural plate and closing of the cranial and caudal neuropores to form the neural tube. Human embryos have multiple sites of neural tube closure. Neural tube closure defects occur in about 1/1000 live births.
