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58 Cards in this Set
- Front
- Back
3 types of pathologies of SCI, in order of prevalence
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contusion
laceration massive compression |
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2 types of contusion
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solid core
cyst |
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2 waves of contusion injury
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primary zone
secondary zone |
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the primary zone of SCI is the zone of...
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mechanical destruction
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two subtargets within the primary zone
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gray matter
white matter |
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what occurs during spinal contusion in the gray matter of the primary zone?
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IMMEDIATE neuronal death --> Ca2+ influx --> release of excitotoxic NTs --> necrosis predominates
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what occurs during spinal contusion in the white matter of the primary zone?
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tract and propriospinal axons degenerate
(observe demyelination with Weigert stain) |
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what type of cell death predominates in the secondary zone?
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PCD
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2 signs of pathology seen with Weigert stain in the secondary zone with contusion.
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glial scarring
formation of fluid filled cyst cavity |
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what causes glial scarring in secondary zone?
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proliferation of astrocytes and macrophages that clean up debris in wake of trauma
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following spinal contusion, what is the "region of partial preservation"?
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secondary zone
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spared regions CAUDAL to injury often contain what?
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"healthy" neurons and intact neural circuits mediating reflexes (skeletal muscle, urogenital)
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3 examples of endogenous responses to SCI that show spontaneous, if limited, repair ability
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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 |
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7 things that happen to injured ascending and descending neurons
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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 |
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3 mechanisms that HINDER repair and regeneration of axons
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glial scar and cyst --> physical barriers to regenerating axons
growth inhibiting factors are upregulated Nogo-A expressed by oligodendrocytes, inhibiting axonal regeneration |
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what is Nogo-A?
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myelin-associated protein
axon guidance molecule inhibits axon regeneration ("locks" pathways in an adult state after development) |
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what is chondroitin sulphate proteoglycan?
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found in scar tissue
block growth of axons & inhibit sprouting |
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effect of antibodies to Nogo-A after SCI
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enhance axon regrowth across injury and promote functional recovery
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absence of glial scaffold hinders...
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axons attempting to regrow through the lesion
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neuronal apoptosis in penumbra may limit...
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repair of damaged circuitry
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neuronal growth and development are regulated by proteins called ____
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neurotropic factors
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one large class of neurotropic factors
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neurotrophins
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neurotrophins are NECESSARY for what?
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neuronal survival, differentiation and axon regrowth
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neurotrophins also function in (3 things):
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axon guidance
synaptic plasticity neurotransmission |
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mammalian neurotrophins are highly ____
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cell-specific
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4 neurotrophins important to axon regeneration
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nerve growth factor (NGF)
brain-derived growth factor (BDNF) neurotrophin-3 (NT-3) neurotrophin-4/5 (NT-4/5) |
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neurotrophins in the adult nervous system are capable of preventing _____ and modulating _____
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neurotrophins in the adult nervous system are capable of preventing CELL DEATH and modulating SYNAPTIC EFFICACY
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primary target of neurotrophins?
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neuron's GROWTH CONE
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growth cone
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protuberance on neuron in which their elongating axons terminate
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target cells of developing axons secrete ONE/A VARIETY of neurotrophins?
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target cells secrete A VARIETY of neurotrophins toward the developing axon
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How did the patient in class initiate micturition?
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he facilitates a spinal micturition reflex with abdominal compression
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Administration of a muscarinic receptor antagonist does what?
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inhibits detrusor muscle contraction
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Pain that may arise from abnormal activity of central neurons in the ANTEROLATERAL system and not from sensory afferents.
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Phantom pain
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Persistent, burning pain associated with partial injury to a peripheral nerve
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Causalgia
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the medial lemniscus originates from neurons in the _____
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gracile and cuneate fasciculi
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Injury to which structure would most likely produce sensory deficits in the lower limbs and disruption of bowel and bladder function?
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cauda equina
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nerves from the cauda equina
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3-5 lumbar,
5 sacral, 1 coccygeal nerve. |
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spinocerebellar tract
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from spinal cord to IPSILATERAL cerebellum
carries PROPRIOCEPTIVE signals |
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spinocerebellar tracts on the anterior side of the body carry signals from...
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GTO
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spinocerebellar tracts on the posterior side of the body carry signals from...
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muscle spindles
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a spinal lesion restricted to the LEFT GRACILE FASCICULUS would most likely present with impairment of vibration/position sense in the _____
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LEFT LEG
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Where does the decussation of the DC-ML tract occur?
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ABOVE the gracile/cuteneous fasciulus
BELOW the medial lemniscus |
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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 |
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What two neurotrophic factors encourage regeneration of
Ia muscle spindle afferents |
Ia muscle spindle afferents:
BDNF NT-3 |
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what neurotrophic factor encourages the regeneration of nociceptors?
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nociceptors:
NGF |
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what neurotrophic factor encourages the regeneration of rubrospinal neurons?
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BDNF
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what neurotrophic factor encourages the regeneration of Clarke's nucleus neurons?
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NT-3
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Clarke's nucleus neurons are in the _____ tract
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posterior spinocerebellar
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2 types of axon attracting molecules
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CAMs
Netrin |
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3 types of axon repelling molecules
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semaphorins
Netrin Nogo |
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7 strategies for SCI treatment
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Protect
Clean up mess Stimulate axon regrowth Bridge the lesion Enhance axon regrowth in white matter Promote axonal conduction Rehabilitation |
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Which TRACT mediates "fast" or "sharp" pain?
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Spinothalamic
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Which TRACT mediates "slow/aching" pain?
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spinomesencephalic
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spinothalamic and spinomesencephalic tracts are both part of which neural system?
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anterolateral
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Tabes dorsalis and syringomyelia both produce bilateral sensory losses. What is the major difference in presentation?
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Tabes dorsalis - bilateral loss of thick, myelinated fibers (motion, vibration, pressure)
Syringomyelia - bilateral loss of thin, unmyelinated fibers (A-d & C) - pain & temperature |
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What happens to micturition function when the spinal cord lesion is above the LUMBAR region?
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automatic/uninhibited bladder
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What happens to micturition function when spinal cord lesion is in the SACRAL region?
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flaccid bladder
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where are muscarinic receptors usually found?
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muscarinic receptors (mAChRs) are end-receptors receiving cholinergic signals from POSTGANGIONIC PARASYMPATHETICS
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