L7 HS Flashcards
Early embryological events in the
formation of the nervous system include
a sequence of six cellular processes?
(1) neurogenesis (proliferation),
(2) cell
migration,
(3) cell differentiation,
4)synaptogenesis,
(5) neuronal cell death,
(6) synapse rearrangement
what does primary neurogenesis give rise to ?
and secondary ?
primary - projection neurons
secondary - inter neurons
laminar structures in brain ?
cortex, cerebellum and hippocampus
what is the ventricular zone VZ?
epithelium lining brain vesicles in neural tube
site of primary neurogenesis
As neurons are produced they move from the VZ to ?
outer surface of mantle zone increase in neural tube thickness
types of migration ?
Interkinetic nuclear movement (proliferation)
Migration of cells to form neocortex (differentiation)
Which signals mediate neuronal migration?
Extracellular cues
Intracellular signalling pathways
Rearrangement of cytoskeletal components
neurons have to migrate long distnaces before they can what ?
differentiate
The wall of the proencephalon-neuronal tube
structure is composed of one continuous
sheet of neuroepithelial cells of what type ?
pseudostratified columnar epithelium
what are pseudostratified neuro ep cells ?
neural epithelium cells that are elongated bipolar cells and span the entire wall of the cerebrum
up side down orientation - apical surface near ventricle and basal near - basal lamina
what type of migration is associated with the neural psuedostrat epithelium ?
inter kinetic neural migration
nuclear movement is linked to ?
cell cycle
S phase DNA synthesis occurs at ?
G2 what happens ?
G1 what happens ?
basal part of VZ
G2 = cells bodies move to apical part and mitosis
G1 = neuron bodies move basally
Corticogenesis what is ?
neurogenesis, proliferation, differentiation and migration to form the neocortex
Inside-out migration from ventricular zone; youngest most superfical layer
List 5 embryonic zones involved in corticogenesis
VZ,IZ,SP,CP,MZ Ventricular zone intermediate zone sub-plate cortical plate mantle zone
give rise to 6 layered cortex
what type of migration contributes to columnar organisation ?
radial migration and glial guided migration
neuronal migration routes
radial migration - progenitor zone (VZ) towards surface of the brain following radial layout of neuronal tube
(parallel to Radial Glia)
tangental migration - non-radial) Cells migrate orthogonally to the direction of radial migration (orthogonal to RG)
Multipolar Migration (non-radia
Radial migration involves ?
Glial-Guided Locomotion Somal Translocation (glial independent)
Radial glial scaffold provides a substrate for
directed neuronal migration
The columnar organization of the mammalian
neocortex develops from the RG scaffold
what are RGC?
specialized glial cells that extend long radial processes towards overlying cerebral wall
where does the basal progenitor cells divide to give 2 neurons ?
sub ventricular zone
RGCs under what type of movement ?
interkinetic nuclear movement in VZ
mitosis at apical VZ
S phase dna syn at basal VZ
cortical projection neurons migrate through what three phases ?
gial guided locomotion
somal translocation
multipolar
cortical interneurons migrate ?
tangentially along the marginal zone and intermediate zone from their origins in the basal forebrain.
later they migrate on the cortical plate
glial guided locomotion when does it occur ?
neurons go from where to where
during late corticogenesis - delivers neurons from the cortical plate to the mantle and subplate
usinf RG scaffold neurons use a salatory locomotion short bursts of movement with stops
35um/h
