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58 Cards in this Set

  • Front
  • Back
3 types of pathologies of SCI, in order of prevalence
contusion

laceration

massive compression
2 types of contusion
solid core

cyst
2 waves of contusion injury
primary zone

secondary zone
the primary zone of SCI is the zone of...
mechanical destruction
two subtargets within the primary zone
gray matter

white matter
what occurs during spinal contusion in the gray matter of the primary zone?
IMMEDIATE neuronal death --> Ca2+ influx --> release of excitotoxic NTs --> necrosis predominates
what occurs during spinal contusion in the white matter of the primary zone?
tract and propriospinal axons degenerate

(observe demyelination with Weigert stain)
what type of cell death predominates in the secondary zone?
PCD
2 signs of pathology seen with Weigert stain in the secondary zone with contusion.
glial scarring

formation of fluid filled cyst cavity
what causes glial scarring in secondary zone?
proliferation of astrocytes and macrophages that clean up debris in wake of trauma
following spinal contusion, what is the "region of partial preservation"?
secondary zone
spared regions CAUDAL to injury often contain what?
"healthy" neurons and intact neural circuits mediating reflexes (skeletal muscle, urogenital)
3 examples of endogenous responses to SCI that show spontaneous, if limited, repair ability
astrocytes, progenitor cells and microglia migrate from PNS

proliferation in the central canal region produces precursor cells that differentiate into glial cells

injured ascending and descending axons show some repair
7 things that happen to injured ascending and descending neurons
limited sprouting

degenerating myelinated axons phagocytosed

demyelination of surviving axons

some attempt regrowth, but fail to regenerate long distance

new circuit formation

some spontaneous remyelination occurs

muscle atrophy
3 mechanisms that HINDER repair and regeneration of axons
glial scar and cyst --> physical barriers to regenerating axons

growth inhibiting factors are upregulated

Nogo-A expressed by oligodendrocytes, inhibiting axonal regeneration
what is Nogo-A?
myelin-associated protein

axon guidance molecule

inhibits axon regeneration ("locks" pathways in an adult state after development)
what is chondroitin sulphate proteoglycan?
found in scar tissue

block growth of axons & inhibit sprouting
effect of antibodies to Nogo-A after SCI
enhance axon regrowth across injury and promote functional recovery
absence of glial scaffold hinders...
axons attempting to regrow through the lesion
neuronal apoptosis in penumbra may limit...
repair of damaged circuitry
neuronal growth and development are regulated by proteins called ____
neurotropic factors
one large class of neurotropic factors
neurotrophins
neurotrophins are NECESSARY for what?
neuronal survival, differentiation and axon regrowth
neurotrophins also function in (3 things):
axon guidance

synaptic plasticity

neurotransmission
mammalian neurotrophins are highly ____
cell-specific
4 neurotrophins important to axon regeneration
nerve growth factor (NGF)

brain-derived growth factor (BDNF)

neurotrophin-3 (NT-3)

neurotrophin-4/5 (NT-4/5)
neurotrophins in the adult nervous system are capable of preventing _____ and modulating _____
neurotrophins in the adult nervous system are capable of preventing CELL DEATH and modulating SYNAPTIC EFFICACY
primary target of neurotrophins?
neuron's GROWTH CONE
growth cone
protuberance on neuron in which their elongating axons terminate
target cells of developing axons secrete ONE/A VARIETY of neurotrophins?
target cells secrete A VARIETY of neurotrophins toward the developing axon
How did the patient in class initiate micturition?
he facilitates a spinal micturition reflex with abdominal compression
Administration of a muscarinic receptor antagonist does what?
inhibits detrusor muscle contraction
Pain that may arise from abnormal activity of central neurons in the ANTEROLATERAL system and not from sensory afferents.
Phantom pain
Persistent, burning pain associated with partial injury to a peripheral nerve
Causalgia
the medial lemniscus originates from neurons in the _____
gracile and cuneate fasciculi
Injury to which structure would most likely produce sensory deficits in the lower limbs and disruption of bowel and bladder function?
cauda equina
nerves from the cauda equina
3-5 lumbar,
5 sacral,
1 coccygeal nerve.
spinocerebellar tract
from spinal cord to IPSILATERAL cerebellum

carries PROPRIOCEPTIVE signals
spinocerebellar tracts on the anterior side of the body carry signals from...
GTO
spinocerebellar tracts on the posterior side of the body carry signals from...
muscle spindles
a spinal lesion restricted to the LEFT GRACILE FASCICULUS would most likely present with impairment of vibration/position sense in the _____
LEFT LEG
Where does the decussation of the DC-ML tract occur?
ABOVE the gracile/cuteneous fasciulus

BELOW the medial lemniscus
start/stop point of neurons in DC-ML tract

first:

second:

third:
start/stop point of neurons in DC-ML tract

first: receptor to gracile/cuneate nucleus

second: gracile/cuneate nucleus to thalamus

third: thalamus to primary sensory cortex
What two neurotrophic factors encourage regeneration of

Ia muscle spindle afferents
Ia muscle spindle afferents:

BDNF

NT-3
what neurotrophic factor encourages the regeneration of nociceptors?
nociceptors:

NGF
what neurotrophic factor encourages the regeneration of rubrospinal neurons?
BDNF
what neurotrophic factor encourages the regeneration of Clarke's nucleus neurons?
NT-3
Clarke's nucleus neurons are in the _____ tract
posterior spinocerebellar
2 types of axon attracting molecules
CAMs

Netrin
3 types of axon repelling molecules
semaphorins

Netrin

Nogo
7 strategies for SCI treatment
Protect
Clean up mess
Stimulate axon regrowth
Bridge the lesion
Enhance axon regrowth in white matter
Promote axonal conduction
Rehabilitation
Which TRACT mediates "fast" or "sharp" pain?
Spinothalamic
Which TRACT mediates "slow/aching" pain?
spinomesencephalic
spinothalamic and spinomesencephalic tracts are both part of which neural system?
anterolateral
Tabes dorsalis and syringomyelia both produce bilateral sensory losses. What is the major difference in presentation?
Tabes dorsalis - bilateral loss of thick, myelinated fibers (motion, vibration, pressure)

Syringomyelia - bilateral loss of thin, unmyelinated fibers (A-d & C) - pain & temperature
What happens to micturition function when the spinal cord lesion is above the LUMBAR region?
automatic/uninhibited bladder
What happens to micturition function when spinal cord lesion is in the SACRAL region?
flaccid bladder
where are muscarinic receptors usually found?
muscarinic receptors (mAChRs) are end-receptors receiving cholinergic signals from POSTGANGIONIC PARASYMPATHETICS