Development (4)

Question 1

what is the cell type order in the genesis of nervous system cells

Answer 1

stem, progenitor, blast, specialized

Question 2

what are the different phases of neural development

Answer 2

cell proliferation, cell migration, cell differentiation

Question 3

what is cell proliferation

Answer 3

cell division

Question 4

why does the cleavage plane in cell proliferation matter

Answer 4

it determines the fate of the daughter cells because there could be an unequal division of transcription factors

Question 5

what are the different stages of pathway/axon formation

Answer 5

1. pathway selection: three possible routes at optic chiasm
2. target selection: which part of the brain (ex. which thalamic nucleus)
3. address selection: which layer/specific cells (ex. which layer of LGN)

Question 6

what is a growth cone

Answer 6

growing tip of a neurite

Question 7

what are the components of a growth cone

Answer 7

filopodia (fingers) and lamellipodia (space in between the fingers)

Question 8

what is apoptosis

Answer 8

programmed cell death

Question 9

what is a mechanism via which proliferation is arrested

Answer 9

notch-1 signaling; if new cell contains notch-1, it will stop dividing and induce neuron/glia maturation

Question 10

which way to pyramidal cells and astrocytes migrate

Answer 10

vertically

Question 11

which way do interneurons and oligodendroglia migrate

Answer 11

horizontally

Question 12

what order to cells migrate during cortical development

Answer 12

subplate, layer 6, layer 5, layer 4, layer 3, layer 2, layer 1

Question 13

what is the role of semaphorin 3A in cell differentiation

Answer 13

it attracts the apical dendrite of a pyramidal cell and repels the other dendrites

Question 14

what is fasciculation

Answer 14

when axons can “group” together and all migrate together if they are in close proximity

Question 15

what are the main molecules mediating fasciculation

Answer 15

integrin is on the cell and laminin is the receptor on the extracellular matrix

Question 16

describe the role of netrin, slit, and robo

Answer 16

netrin is a chemoattractant and once the cell gets to the midline, it expresses more robo receptors which makes slit repel the cell

Question 17

how do neurons form synapses with each other

Answer 17

1. dendritic filopodium contacts the axon
2. synaptic vesicles in axon move toward the presynaptic terminal towards the synapse
3. receptors are created on the postsynaptic membrane (on dendrite)

Question 18

what is the purpose of trophic factors in cell survival

Answer 18

not enough trophic factors will lead to apoptosis

Question 19

what is synaptic capacity

Answer 19

there is only a small number of places that a neuron can connect to another cell

Question 20

how is neural activity important in fine tuning the synaptic connections

Answer 20

if a synapse is not used, it will be eliminated; if cells are not firing together anymore, they will become unlinked

Question 21

what is synaptic segregation

Answer 21

refinement of synaptic connections by spontaneous activity

Question 22

how are synaptic modifications achieved

Answer 22

the cell that produces stronger effects will innervate the target cell more

Question 23

how does neural activity lead to synaptic strengthening

Answer 23

when there is pre and post synaptic activity, the synaptic connection will become stronger (neurons that fire together wire together)

Question 24

what are some effects of environmental enrichment on brain development

Answer 24

thicker cortex, better blood supply, larger dendritic fields

Question 25

how do NMDA receptors work

Answer 25

NMDA channels have a Mg block which is lifted by depolarization (AP); Ca can then be released (only NMDA channels can let Ca and Na into the cell at the same time)

Question 26

why are NMDA receptors coincidence detectors

Answer 26

they detect activity from both synaptic sides
pre synaptic side detects NT release
post synaptic side detects depolarization

Question 27

what NT does the NMDA receptor bind

Answer 27

glutamate