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23 Cards in this Set
- Front
- Back
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Neural tube defects |
X anterior neuropore closure ->anencephaly X posterior neuropore closure -> spina bifida: - occulta (benign, seen on X-rays) - meningocele (meninges + CSF) - meningomyolocele (... + spinal cord) - rachischisis (spinal cord exposure) => SC/nerve roots dmg -> LE & bladder dysfx |
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Neural crest -> neuronal cells |
Cells at the lip of neural tube closure => all of PNS (-somatic & preganglionic ANS): - DRG & all sensory n's (-optic n, CN II) - CN ganglia - autonomic ganglia (also gut) - adrenal medulla |
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Neural crest -> non-neuronal cells |
- Schwann cells & satellite cells - leptomeninges (pia, arachnoid) - bone & CT of face & skull |
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Neural tube initiation |
Ectoderm -> BMP -> ectoderm Notochord -> noggin, chordin, folistatin --| BMP => neuroectoderm |
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Ventral vs. dorsal neural tube differentiation |
Dorsal - neural crest (-> alar plate -> d. horn): TGF-β: BMPs, dorsalin, Vit A, RA, noggin Ventral - notochord (-> basal plate -> v. horn): Shh, chordin, RA, noggin |
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Sonic Hedgehog as a ventralizing factor |
PTC --| SMO Shh -> PTC (R) => SMO -> Gli (TF's) - cholesterol attached to N-term. -> cleavage => proper fx of A-terminus (X statins!) - ventralizing activity demonstrated by extra NC - defects -> holoprosencephaly |
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Neuron organization w/in spinal cord |
(Dorsal/lateral) Somatic sensory n's Visceral sensory n's ----- sulcus limitans ----- Visceral motor n's Somatic motor n's (Ventral/medial) |
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RA -> ? |
Concentrated in cervical area; determines caudal identity w/ diffusion -> activates TFs -> Hox genes regulation => rhombomere ID |
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Fate of neural tube vesicles |
Optic -> retinas of eyes Telencephalic -> lateral ventricles Diencephalic -> 3rd ventricle Mesencephalic -> cerebral aqueduct Metencephalic & myelencephalic -> 4th ventricle Metencephalon, 4th ventricle -> cerebellum |
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Vertebrate neuroepithelium divisions |
1-cell layer thick neural tube walls, connected w/ both lumen & pial surface -> Pial surface: S-phase -> Neural tube lumen: M-phase (mitosis) -> repeat |
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Neuroblast cell division |
Cell surface signaling molecules: notch-1 (apical) & numb (basal) Vertical division -> equal Horizontal division -> ↑ notch => post-mitotic -> differentiation => neurons & glia on pial surface (mantle zone) |
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Lateral inhibition in neural differentation |
Notch + adjacent delta --| neurogenin (-> delta) ↓ notch -> ↑ neurogenin => - ↑ delta --| neurogenin in adjacent cells -> glioblasts - helix-loop-helix genes -> neuroblast |
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Formation of layers of neural tube |
Postmitotic cells: ventricular zone -> mantle zone (gray matter); axons: -> periphery = marginal zone (white matter) |
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Migration via cell-cell interaction |
Radial glia: ventricular -> pial surface - neuroblasts crawl along (ex.: -> pial surface = cortex) |
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Migration of cortical neurons |
Order of migration - inside-out: Layer I = marginal zone (closest to pial surface) [Cajal-Retzius cells secrete reelin -> migration] Layer VI (stays closest to ventricular zone) Layer V -> b/w I & VI Layer IV -> b/t I & V, etc. Layer III Layer II (ends by 16th w) |
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Processes of neural development |
Mitosis & proliferation Migration Differentiation Synaptogenesis Apoptosis Synaptic rearrangement/plasticity |