neural damage and recovery Flashcards

1
Q

apoptosis

A

programmed death of as much as 50% of cells.. those that aren’t well-connected, or we already have a redundant connection

  • programmed death, normal
  • phagocytosis is excited without any explosive, leaky, mess
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2
Q

synaptic pruning

A

process of pruning away axonal connections that are not competitive, stimulated, used or needed

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3
Q

necrosis

A

messy and unwanted cell death

  • phagocytosis has a big mess on its hands
  • can leave a hole in the cell tissue
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4
Q

spinal cord injury - trauma

A
  • bending, tearing, cutting, dislocation, hyperextension, hyper flexion
  • damage depends on level of SC injury; degree of injury
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5
Q

spinal cord injury - disease

A
  • occlusion of arteries needed to supply neurons in the spinal cord
  • anterior spinal artery occulsion due to atherosclerotic disease
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6
Q

amytrophic lateral sclerosis (ALS)

A
  • degeneration of neurons in the spinal cord
  • progressive degernation of lateral corticospinal tracts
  • loss of anterior horn cells throughtout SC and BS
  • muscle atrophy, paresis, death
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7
Q

transverse myelitis

A
  • inflammation of the spinal cord
  • progressive inflammation and attack on the myelin at one level of the SC
  • better hope for recovery
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8
Q

neuroplasticity

A

-network itself may reorganize its efforts after cell death

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9
Q

primary neuronal cell death

A

-immediate death/degeneration

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10
Q

secondary neuronal cell death

A
  • occurs hours/days/weeks after primary trauma

- depends on blood flow, edema, inflammation, and integrity of the BBB

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11
Q

causes of primary cell death

A
  • anoxia (total lack of oxygen)
  • hypoxia (insufficient oxygen)
  • trauma (damage to cytoskeleton, intracellular organelles, damage to BBB, damage to axon causing cell death)
  • toxic/metabolic poisoning (disrupts cellular mechanisms)
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12
Q

axonal (retrograde) reaction

A
  • secondary cell death
  • changes and/or death to the cell body
  • as a result to damage to the axon
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13
Q

process of cell death

A
  • internal changes to cell body take place
  • cell body swells and nucleus becomes displaced
  • disruption of BBB and deterioration of cytoskeleton occurs
  • cell body disintegrates, explodes
  • macrophages take over to liquify the mess and necrotic tissue
  • may take several months to years
  • tissue removal will leave a cavity in the brain
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14
Q

wallerian (anterograde) degeneration

A

-degeneration to the distal part of the axon.. away from the site of actual injury

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15
Q

the process of wallerian deregulation

A
  • the distal part of the axon will swell within 24 hours
  • within days the muscles which were previously innervated by this axon will become denervated
  • within a week, the axon and its myelin are disintegrated
  • macrophages and phagocytes take over to liquify and remove the dead tissue
  • may take months to years to remove everything
  • in the meantime, macrophages and phagocytes block the site of the injury
  • DAMAGE MOVES DOWNSTREAM
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16
Q

PNS regeneration

A
  • any regeneration of axons generally occurs in the PNS, not the CNS
  • more likely if the nerve is just crushed not severed
  • axon begins to degenerate distal to injury (wallerian)
17
Q

schwann cells

A

work to promote growth of new axon sprouts, growth cones, at the site of injury
-part of PNS regeneration

18
Q

CNS regeneration

A
  • macrophages and phagocytes go to work, but takes months or years to clean up, and is less efficient than in PNS
  • meanwhile, the neurons impacted by this axon injury tend to die
  • CNS neurons are interdependent (when some die, many die, waste)
19
Q

oligodendrocytes

A

in the CNS

-have minimal capacity to promote growth of new myelin or sprouting of axons

20
Q

what role do astrocytes play?

A

-come in and form a barrier around the dying cel, making it even more difficult or impossible to regenerate