lecture 2 - claudia racca Flashcards
neurulation transforms neural plate into what
neural tube
from the crest theres the PNS and from the tube theres the
CNS
in the neural tube what is at the rostral end (front)
the forebrain
what is in the middle of the neural tube
the midbrain
what is at the caudal end of the neural tube
the hindbrain
the forebrain develops what vesicles
telencephalic and optic vesicles
which vesicles go over the diencephalon
the telencephalic vesicles (2 cerebral hemispheres)
at the rostral end of the telencephalon what is there
olfactory bulbs (nose) and optic cups (eyes)
what are the grey matter structures in the forebrain
cerebral cortex
thalamus
hypothalamus
basal telencephalon
neurone generation (cell proliferation):
cells migrate up towards the surface from the ventricle and the DNA is…
replicated
they then migrate back to the ventricular surface and they divide.
when the division of the cell is vertical what type of cell division do we get?
symmetrical cell division and the two cells will become radial glial cells
when the division of the cell is horizontal what type of cell division do we get
asymmetrical cell division. one cell will stay in the ventricular zone as a radial glial cell and the other one will be a neuronal precursor and migrate
the daughter cells for each new layer of cortex migrate up past deeper layer
layer 6 cells are made first then layer 5 cells etc
how do daughter cells migrate
along structure fibres provided by radial glial cells
where does the daughter cell differentiate
as soon as it arrives at the cortical plate
neurites sprout off the cell body forming
dendrites and axon
what does a growing axon have as its tip
growth cone
what does the growth cone do
secreted proteases that digest fibrous proteins in the extracellular matrix allowing its elongation
what extends from the lamellipodia
filopodia
the filopodia grab hold of other proteins in the matrix via…
integrins (cell surface molecules)
what do integrins bind do in the matrix
laminins
this causes the axon to elongate
cell adhesion molecules (CAMs) on growing axons causes what
multiple axons to stick together allowing an easier elongation (fasciculation)
what are chemorepellents
particular surface markers on proteins in the extracellular matrix that repel axons
axons originating from different areas express different CAMs which are attracted to different markers in the target tissue. this is the __________ hypothesis
chemoaffinity
target tissues also release ________ that guide axons towards them
chemoattractants (e.g netrins)
attraction molecules causes increase of calcium ion concentration from where
endoplasmic reticulum
causes the axon to move in that direction
repulsive molecules causes increase of calcium ions from…
other sources
causes the axon to move in the opposite direction
if the neuron expresses DDC receptor what will netrin-1 cause
attraction
if the neuron expresses UNC5H receptor what will netrin-1 cause
repulsion
what are signals that stop growth of axons
absence or certain glycoproteins in the EC matrix
specific diffusible chemicals from target tissue (e.g NTs)
when the axon is in contact with the target the growth cone collapse and ______ is formed
synapse
synapse formation:
secretion of proteins by growth cone and target membrane interact and stimulate…
- formation of postsynaptic receptors
- formation of presynaptic terminal
- Ca entry into growth cone induces cytoskeleton rearrangment release transmitter
what is usually the post synapse
dendrite of another neuron
