Von Bartheld-Regeneration Flashcards

1
Q

T/F
when axons in the peripheral nervous system are cut or crushed, they can regenerate their axons and connect with their original target, and lost function can be restored.

A

T

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2
Q

What are the three steps required for successful regeneration?

A
  1. cell body survival
  2. axon regrowth
  3. axon reconnection w/ target
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3
Q

T/F
when axons in the central nervous system are cut or crushed, they can regenerate their axons and connect with their original target, and lost function can be restored.

A

F, axon regeneration is very limited here

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4
Q

The regenerative capacity depend on (blank) factors as well as interactions of neurons with other cells.

A

intrinsic

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5
Q

T/F

The age of the neuron influences cell survival

A

T

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6
Q

T/F

developing neurons require axonal transport of trophic factors

A

T

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7
Q

What is the name of the end swelling formed after a nerve transection?

A

growth cone

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8
Q

(blank) exits the growth cone and senses molecular cues in the environment to determine the growth path

A

filopodia

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9
Q

Transection of a nerve fiber triggers a complex set of events where?

A

in nerve cell body,
in axon proxim and distal to lesion
in supporting glial cells
other non-neural cells

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10
Q

The cell body response is induced by the interruption of (retrograde/anterograde) axonal transport of trophic factors from the target

A

retrograde

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11
Q

What are the 2 growth factors involved in the cell body response?

A

CNTF and GDNF

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12
Q

T/F there is no change in gene expression in the cell body response

A

F!!! There is change in gene expression in the cell body response

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13
Q

In the cell body response to injury,
Proteins involved in functions of mature neutrotransmission are generally (increased/decreased) while those involved in the regerenative process such as GAP 43 are (increased/decreased)

A

decreased

increased

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14
Q

Myelin sheaths (distal/proximal) to the cut/crush degenerate

A

distal

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15
Q

(blank) cells proliferate and phagocytose the degenerating myelin in nerve injury.

A

schwann cells

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16
Q

T/F macrophage infiltration is involved in neuronal regeneration

A

T
(macrophages invade the site of injury and degeneration and participate in phagocytosis of old myelin and the distal axon segments)

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17
Q

Wallerian degeneration occurs in (proximal/distal) axons

A

distal

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18
Q

Wallerian degeneration is an (active/passive) process .

A

active

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19
Q

What is “wallerian-like degeneration”?

A

degenerative diseases that resemeble wallerian degeneration

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20
Q

Shwann cells express (blank) on their surface that promote new axon growth

A

cell adhesion molecules (CAM).

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21
Q

(blank) cells and ensheathing (wrapping of myelin around the axon) produce trophic factors that stimulate axon growth.

A

glia cells

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22
Q

Axon growth is slow or fast?

A

slow (weeks to months)

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23
Q

Trophic factors support the survival of the neuron (blank)

A

cell body

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24
Q

Secretion of (blank) from shwann cells may also promote the growth of the axon along the pathway to the target

A

growth factors

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25
Q

What are some important growth factors for neuron regeneration?

A

NGF, BDNF, GDNF, CNTF, FGFs, and IGFs

26
Q

T/F

All growth factors work on all types of cells

A

F

27
Q

Axons grow in a path that follows what cell type?

A

schwann cells

28
Q

Do regrown axons innervate the target cells of the orignial axons?

A

Sometimes but not ususally (but they attempt to)…. BUT if they do reconnect they they become myelinated and return to their former caliber

29
Q

Are regenerated axons selective or nonselective in target cell innervation?

A

nonselective

30
Q

What is a downside to nonselective axonal regeneration?

A

Some functional contacts may be inappropriate

31
Q

Will a crushed or cut nerve have more innervation of original targets?

A

crushed (cut is more severe of an injury)

32
Q

CNS regeneration is limited by the axon or cell body?

A

axon

33
Q

In the CNS, Wallerian degeneration is (faster/slower) than wallerian degeneration in the PNS

A

SLOWER

34
Q

What 3 criteria make regeneration more difficult in the CNS?

A
  1. slow wallerian degeneration
  2. mylein debris blockage
    3 astrocytic scars via astrocyte proliferation
35
Q

T/F

Failure to regenerate in the CNS is due to a lack of intrinisc capacity to regenerate

A

F

36
Q

How can you regenerate neurons in the CNS effectively?

A

utilizing a peripheral nerve graft containing schwann cells

37
Q

What type of glial cells inhibit axon regrowth?

A

oligodendrocytes

38
Q

Oligodendrocytes express (blank) protein which causes growth cone (collapse/expansion)

A

myelin associated glycoproteins (MAGS and NOGO proteins)

collapse

39
Q

loss of neurons can occur as a result of (blank), (blank), or (blank)

A

injury, toxins (drugs) or idiopathic reasons (autoimmune or genetic).

40
Q

What neurons are routinely generated in teh adult mammalian nervous system?

A

ONLY the olfactory and taste receptor cells and small number of interneurons in the dentate gyrus and in the olfactory bulb

41
Q

how can you lose hair cells in the organ of corti?

A

via acoustic trauma or ototoxic drugs

42
Q

Do hair cells regenerate?

A

no

43
Q

How can you lose retinal ganglion cell?

A

optic nerve trauma and thus you get blindness

44
Q

What are some trophic factors that may help retain retinal ganglion cells after trauma?

A

BDNF and GDNF

45
Q

What area of the brain degenerates in parkinsons disease?

A

substantia nigra (dopaminergic neurons)

46
Q

What is the degeneration in parkinsons thought to be caused by?

A

trophic dysfunctions

47
Q

Recently scientists have decided that trophic factors can help with parkinsons but they are having a hard time getting them to the midbrain, why is this?

A

because trophic factors are rapidly removed from the vasculature and do not cross the blood brain barrier

48
Q

What are some new strategies for treating parkinsons?

A

infuse trophic factor into the CSF, implant slow release compounds, design carriers to transport factors across BBB, to graft cell into the midbrain which produce trophic factor, develop low molecular weight agonists which cross BBB, use stem cells to generate dopamine-producing neurons for transplantation

49
Q

What degenerates in Alzheimer’s disease?

A

cholinergic basal forebrain neurons due to trophic dysfunction

50
Q

What degenerates in amyotrophic lateral sclerosis?

A

lower and upper motor neurons

51
Q

Is amyotrophic lateral sclerosis fatal?

A

yes (usually within a few years)

52
Q

What is being used in clinical trials to treat ALS?

A

BDNF,CNTF and other growth factors

53
Q

What degenerates in retinitis pigmentosa?

A

photoreceptors (rods and cones)

54
Q

What is a way to get sight back in retinitis pigmentosa? Why does this work?

A

put in a subretinal implant
because your retinal ganglion cells are retained but you need photoreceptors so you implant the chip that is light sensitive :)

55
Q

Can glia cell degenerate?

A

yes

56
Q

In multiple sclerosis what degenerates?

A

oligodendrocytes and their myelin degenerate (demyelination)

57
Q

What is multiple sclerosis cause dby?

A

an autoimmune reaction due to a shared antigen between CNS myelin and an unknown virus

58
Q

What is the novel strategy for replacing lost neurons?

A

stem cells

59
Q

It is thought that interneurons in the olfactory bulb and in the hippocampus derive normally from (blank), even in the adult

A

stem cells

60
Q

How do you introduce stem cells into in vitro?

A

with trophic factors to promote differentiation

61
Q

What do you need for a stem cell to survive and become a neuron?

A

distinct differentiation, survive the host functionally connect with targets