ANAT 2130 Lecture Notes - Lecture 7: Neural Tube, Dentin, Glioblast
16 Oct 2016
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Document Summary
Outer layer of embryo, the ectoderm, becomes divided into surface ectoderm and neuroectoderm: differentiation occurs by way of primary embryonic induction. Notochord and medial parts of somites lie just deep to ectoderm, in midline of embryo. These structures signal overlying ectoderm t o thicken, forming neural plate. Indication is reciprocal: neural plate is induced to form by inducers. Inducers are then changed by neural plate. Head signals from inducers cause formation of brain, brain causes formation of skull. Tail signals from inducers cause formation of spina cord, spinal cord causes formation of vertebrae. Neural crest leaves neuroepithelium: neural tube sinks beneath surface of body. Migration of neural crest cells from dorsal neural tube to appropriate sites is highly specific. Neural crest cells use chemical pathways in embryo to migrate along specific pathways to their appropriate destination. Numerous tissues not part of nervous system: examples: melanocytes, odontoblasts (produce dentine in teeth), mesodermal derivative in head region (cartilage, bones in face)
