Development (4) Flashcards
what is the cell type order in the genesis of nervous system cells
stem, progenitor, blast, specialized
what are the different phases of neural development
cell proliferation, cell migration, cell differentiation
what is cell proliferation
cell division
why does the cleavage plane in cell proliferation matter
it determines the fate of the daughter cells because there could be an unequal division of transcription factors
what are the different stages of pathway/axon formation
- pathway selection: three possible routes at optic chiasm
- target selection: which part of the brain (ex. which thalamic nucleus)
- address selection: which layer/specific cells (ex. which layer of LGN)
what is a growth cone
growing tip of a neurite
what are the components of a growth cone
filopodia (fingers) and lamellipodia (space in between the fingers)
what is apoptosis
programmed cell death
what is a mechanism via which proliferation is arrested
notch-1 signaling; if new cell contains notch-1, it will stop dividing and induce neuron/glia maturation
which way to pyramidal cells and astrocytes migrate
vertically
which way do interneurons and oligodendroglia migrate
horizontally
what order to cells migrate during cortical development
subplate, layer 6, layer 5, layer 4, layer 3, layer 2, layer 1
what is the role of semaphorin 3A in cell differentiation
it attracts the apical dendrite of a pyramidal cell and repels the other dendrites
what is fasciculation
when axons can “group” together and all migrate together if they are in close proximity
what are the main molecules mediating fasciculation
integrin is on the cell and laminin is the receptor on the extracellular matrix
describe the role of netrin, slit, and robo
netrin is a chemoattractant and once the cell gets to the midline, it expresses more robo receptors which makes slit repel the cell
how do neurons form synapses with each other
- dendritic filopodium contacts the axon
- synaptic vesicles in axon move toward the presynaptic terminal towards the synapse
- receptors are created on the postsynaptic membrane (on dendrite)
what is the purpose of trophic factors in cell survival
not enough trophic factors will lead to apoptosis
what is synaptic capacity
there is only a small number of places that a neuron can connect to another cell
how is neural activity important in fine tuning the synaptic connections
if a synapse is not used, it will be eliminated; if cells are not firing together anymore, they will become unlinked
what is synaptic segregation
refinement of synaptic connections by spontaneous activity
how are synaptic modifications achieved
the cell that produces stronger effects will innervate the target cell more
how does neural activity lead to synaptic strengthening
when there is pre and post synaptic activity, the synaptic connection will become stronger (neurons that fire together wire together)
what are some effects of environmental enrichment on brain development
thicker cortex, better blood supply, larger dendritic fields
