4-Anterolateral System Flashcards
nociception
physiological reception of noxious info elicited by tissue injury
anterolateral system
pain
subjective perception feeling of discomfort or agoinzing sensation
-variable intensity
-elicited by stim of sensory nerve endings
what does anterolateral system transmit
- nociception
- thermal
some nondiscrim and pressure/proprio
aka pain and temp
what tracts in the ALS
- anterior spinothalamic
- lateral spinothalamic
- spinoreticular
- sinotectal
- spinomesencephalic
- spinohypothalamic
neospinothalamic system
aka spinothalamic tract
direct pathway- spinal cord > thalamus > sensory cortex
-conscious
-fast/sharp/well localized short term pain
tracts of paleospinothalamic
- spinohypothalamic
- spinomesencephalic
- spinotectal
paleospinothalamic system
spinoreticular tract
indirect- spinal cord > RF > thalmus > hypothalamus > limbic cortex
NOT enter consciousness
aching, poorly localized, persistent pain
85% of noci fibers
dermatomes
strip of skin inn by pair of spinal nerves
neurons of neospino system
free nerve endings receptors >
1. DRG
2. dorsal horn of spinal cord
3. VPL of thalamus
pathway in dorsal horn
-dorsolateral tract of lissauer with lightly mye axons (white matter) short ascend + descend fibers
-substantia gelatinosa where axons from lissauer synapse (grey matter)
axons will cross in vental white commissure to form spinothalamic tracts
paleo dont cross just syn at laminae
lesion in spinothalamic tract
def in contralateral side bc secondary fibers already crossed
paleospino transmits what
nociception to
1. reticular formation
2. thalamus (intralaminar nuclei)
3. hypothalamus
4. midbrain (sup colliculi, PAG)
5. limbic system
triggers reflexes not consciousness
paleo neuron bodies
- DRG
- dorsal horn of spinal cord
spinohypothalamic tract
for ANS and reflex resp to pain to protect body
spinomesencephalic tract
to periaqueductal gray (modulates transmission of nociception)
spinotectal tract
reflex of turning eyes, head, upper trunk in direction of noxious stim
spinoreticular tract
sets off alarm system in resp to pain
reticular formation
arousal
wakefulness
alterness
limbic system
affection/emotion component of pain
spinothalamic tract = what part of the cord
lateral + anterior funiculus
radicular pain pathway
- compress/pinching by herniated disc, bone spur, local ligaments
- irritate dorsal root
- pain-sharp, burning, shooting + paresthesia-numbness, tingling, itching
where to tractotomy
sever spinal cord
- 3 levels above pain
- cross over other side
- one up
to sever second order neurons that synapse with ascending branches of primary
referred pain
nociception transmitted to sensory cortex where somatic structure is mapped
-trick brain that pain is coming from somatic instead of visceral structure
convergence projection theory of visceral pain
syringomyelia
cavitation of spinal cord/enlargement from trauma
-axons in anterior white commissure are stretched and damaged = loss of pain/temp sensation bilaterally
