week 4: neurobiology: spinal cord injury

Question 1

most spinal cord injuries in UK and USA caused by

Answer 1

traffic accident
falls

Question 2

spinal cord injuries age and gender stats

Answer 2

80%+ males
average age: 41
no valid explanation

Question 3

quadriplegia

Answer 3

injury affects lower and upper limbs

Question 4

paraplegia

Answer 4

injury affects lower limbs only

Question 5

impact of SCI lesion

Answer 5

neurotic death of neurons
severs axons
vascular injury may occur (extravasation of blood)
blood brain barrier may break
release of excitatory amino acids

Question 6

if blood brain barrier breaks,

Answer 6

leucocytes invasion and release of toxic cytokines

Question 7

release of excitatory amino acids causes

Answer 7

massive increase in Ca2+
causes excitotoxicity
further damage to cells that may have survived intitial trauma

Question 8

secondary injury

Answer 8

-can continue to grow for months
-Wallerian degeneration
-triggers second invasion of inflammatory cells
-activated macrophages and microglial invasion
-astrocytes proliferate and hypertrophy: glia limitans (scar)

Question 9

Wallerian degeneration

Answer 9

process occurs when axons are severed
axons will die back to soma

Question 10

glia scar

Answer 10

structure that forms around region to try to mend and protect area
forms several weeks after initial injury
formed by astrocytes
proliferation of astrocytes needed
form scar around region to prevent further damage and to restore barrier between blood and spinal cord
produce inhibitory molecules, chemical and physical barrier to regrowth (of axons?)

Question 11

ectopic sprouting

Answer 11

sprouting of axons
abnormal growth
causes abnormal reflexes
can cause hyper-reflexia and spasticity
reorganisation of nociceptors
reorganization of autonomic circuits

Question 12

what can reorgnisation of nociceptors cause

Answer 12

chronic pain syndrome

Question 13

what can reorganisation of autonomic circuits cause

Answer 13

autonomic dysreflexia
dysregulation of autonomic reflexes e.g controlling blood pressure
many of these reflexes are vital for survival

Question 14

spinal shock

Answer 14

occurs immediatly after injury
complete lack of reflexes
areflexia or hypo-reflexia and flaccid paralysis

Question 15

weeks after spinal injury

Answer 15

return of segmental reflexes and hyper-reflexia

Question 16

months after spinal injury

Answer 16

spastic paralysis:
large spasms and clonus

Question 17

plasticity

Answer 17

structural, physiological, chemical change in CNS

Question 18

what do denervation and axotomies result in

Answer 18

reorganisation of networks above and below lesion

Question 19

limited capacity of CNS to repair itself due to:

Answer 19

1. limited neurogenisis
2. spontaneous failure of CNS axon regeneration
3. limited endogenous repair
4. insufficient compensatory plasticity

Question 20

what can we do to help repair

Answer 20

1. reduce secondary damage
2. enhance growth potential
3. eliminate obstacles
4. facilitate synaptic reconnectivity

Question 21

approved pharmacological treatments to help gain function after spinal cord injuries

Answer 21

none

Question 22

locomotor training

Answer 22

based on principle of neuroplasticity
designed to improve movement and mobility
take advantage of functioning circuits
lumbar spinal cord possesses all necessary circuitry to produce rhythmic coordinated alternating locomotor behaviors