Neuronal Development, Survival & Differentiation Flashcards
What is the ratio of neurons to glia cells?
10 % = neurons
90% = gliaCEl
Origin of nerve cells
- Neurons & glia = neuroepithelium, ectoderm
- Microglia = yolk sac
microglia are derived from embryonic mesoderm, which gives rise to cells of the blood and immune system.
Neural tube becomes…
Neural progenitors (single layer, pseudostratified columnar)
What is the process of cell division in progenitor expansion phase (phase 1)?
Symmetrical cell division, interkinetic nuclear migration
The 1st generation of neural tube zones
- Preplate PP - 1st gen neurons = pial surface
- Intermediate zone IZ - axons
- Ventricular zone VZ - proliferative zone, radial glial cell body
How does migration on radial glia work?
The migrating neuron has CDK, neuregulin, NMDA-R1, integrin
The radial glia has integrin, laminin, fibronectin, NGCAM
Non-radial migration
Occurs horizontally, at the same time as radial migration
1. DISTRIBUTION OF INHIBITORY GABAergic neurons
2. Formation of brainstem nucleu
What layers does the preplate form?
- Marginal zone
- Cortical plate
- Subplate (will eventually disappear)
The marginal zone becomes which cortical layer?
Cortical layer I, the first layer
The cortical plate develops …
Inside out, from cortical layer VI (closer to the ventricle) to cortical layer II (closer to the marginal zone or cortical layer 1)
Which zone becomes white matter?
Intermediate zone
The ventricular zone becomes
The subventricular zone.
The embryonic layer: ventricular zone goes away.
Sematophorin 3A
Axon goes down (away from higher concentration of semaphorin = long-range chemorepellent)
Dendrite goes up (pial surface)
This is a long-range cue for growth of axon.
Growth cone
Filopodia = feet = actin bundles
Lamillopodia = notch between feet = actin-myosin meshwork
Growth according to chemical signals.
Cadherins
Diffuse in ECM, contact attraction for the growth cone = the roadway
Ephrin
Contact repulsion, roadway guard rails
Netrins
Chemoattraction for growth cone, long-range cues
Mature neurons can be seen in LM due to
Nissl substance
Lipofuscin is found in
DRG
Sympathetic ganglion
Pyramidal neurons
Neuromelanin
Substantia nigra (dopamine)
Kinesin
Anterograde transport
Slow axonal transport for…
Cytoskeletal properties: neurofilaments, microtubules, axonal matrix
Fast axonal transport
Membrane bound organelles, vesicles, neurotransmitters, neuropeptides