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16 Cards in this Set
- Front
- Back
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Neurulation
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Formation of the neural tube
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Ectoderm
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divides into
Neuroectoderm - medial of the notochord Surface ectoderm -lateral |
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Neural plate
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Developed at the neuroectoderm
Extends cranially from the primitive node overlatys the paraxial mesoderm laterally |
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By the end third week development, all of the following has happened:
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cells at lateral edges of the neural plate proliferate and form NEURAL FOLDS (flanks the NEURAL GROOVE)
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Neural tube
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Formed by fusion of neural folds at the dorsal midline
represents the developing central nervous system |
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Fusion of the neural folds occus where?
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First at the future cervical reggion, and then proceeds cranially and caudally
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How does the neural tube communicate with the amniotic cavity before fusion is complete?
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Via the rostral and caudal neuropores
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By the end of the fourth week...
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Fusion of neural fold is complete
the neural tube represents THE DEVELOPING CENTRAL NERVOUS SYSTEM broader at the cephalic end |
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Three expanded regions of the cephallic end of the neural tube (aka brain vesicles)
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Prosencephalon (forebrain)
Mesencephalon (midbrain) Rhombencephalon (hindbrain) |
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Subdivisions of the prosencephalon
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Telencephalon
Diencephalon |
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Subdivisions of the rhombencephalon
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Metencephalon
Myelencephalon |
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Histology of the early neural tube
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Psuedostratified neuroepithelium
lies between two basal membranes |
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The three zones developed in the neural tube
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1. Ventricular zone - proliferating progenitor cells
2. Intermediate zone (migrating neuroblasts) 3. marginal zone (axons of the developing neurons) |
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What do the neuroepithelium of the neural tube give rise to?
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All the neurons and glia
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Neural Crest
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Edges of the neural fold
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Neural Crest cells
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1. specialized population of cells residing at the neural crest
2. loses contacts with neuroectoderm 3. undergoes epithelial-mesenchymal transformation 4. migrates dorsally and ventrally within the embryo |
