neural damage and recovery

Question 1

apoptosis

Answer 1

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

Question 2

synaptic pruning

Answer 2

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

Question 3

necrosis

Answer 3

messy and unwanted cell death

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

Question 4

spinal cord injury - trauma

Answer 4

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

Question 5

spinal cord injury - disease

Answer 5

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

Question 6

amytrophic lateral sclerosis (ALS)

Answer 6

• 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

Question 7

transverse myelitis

Answer 7

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

Question 8

neuroplasticity

Answer 8

-network itself may reorganize its efforts after cell death

Question 9

primary neuronal cell death

Answer 9

-immediate death/degeneration

Question 10

secondary neuronal cell death

Answer 10

• occurs hours/days/weeks after primary trauma

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

Question 11

causes of primary cell death

Answer 11

• 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)

Question 12

axonal (retrograde) reaction

Answer 12

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

Question 13

process of cell death

Answer 13

• 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

Question 14

wallerian (anterograde) degeneration

Answer 14

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

Question 15

the process of wallerian deregulation

Answer 15

• 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

Question 16

PNS regeneration

Answer 16

• 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)

Question 17

schwann cells

Answer 17

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

Question 18

CNS regeneration

Answer 18

• 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)

Question 19

oligodendrocytes

Answer 19

in the CNS

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

Question 20

what role do astrocytes play?

Answer 20

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