Anterolateral Column Flashcards
unspleasant SENSORY and EMOTIONAL experience associated with actual or potential tissue damage
Pain
Why do people experience pain dif
Genetics: receptor densities, nocieptor threshold, density of innervation, descending control
Past experiences
Complex cognitive perception of noxious stimulus in context of ind genetic makeup, envir,
Pain
Perception of pain is very
individual
decreased sensitivity to pain
hypoalgesia
lack of pain
analgesia
lack of thermal sensation
Athermia
lack of all sensation
anesthesia
heightnened sensitivity to any stimulus
hypersthesia
unpleasant, abnormal sensation, tingling, pringing
Parestheisa
increased pain from normally painful stimulus
hyperalgesia
pain from normally non-painful stimulus
allydynia
Pain that doesn’t go away
pain contineus after complete healing neuropathic
pain occurs in absense of any obvious injury
chronic pain
soft tissue damage causes
nociceptive pain
inflammation of soft tissues causes activation of
nocicpetors terminals in skin
Inflammatory chemicals and immune cells activate receptors on:
free nerve endings of C fibers
a sensitized nociceptor has:
lower threshold and respond
Neruopathis pain is:
nerves directly damaged
Type of feeling we get with neuropathic pain
burns, electrical quiality, allydynia to light touch
does neuropathy respond to NSAIDS or optiates
nope
Anterolateral path is a combination of:
several ASCENDING tracts of fibers
What type of info does the anterolateral system send to cortex
pain and temperature
Damage to anterolateral pathway IG causes
loss of pain and temp sensation below lesion while fine touch and vibrtaion okay
Which is more complex, dorsal column or anterolatera
anterolateral– dif paths and terminates in dif places
Noxious, thermal, chem stimuli activate AP in:
free nerve ending of Adelta or C-fiber nocicpetors of skin or joints
These fibers medate first pain; sharp, fast and pricking, short lasting
Adelta
pain fiber that is reflexive
A-Delta
mediate second pain, delayed burn quality, long lasting and chronic
C-fibers
C fibers are long or short lasting
long
A delta is long or short lastin
short
Where do Central processes of nociceptors enter the lateral dorsal horn
via Dorsal lateral tract of Lissauer
Where do central pain processs synapse once in sp cd
on the sp cd neurons of teh superfical dorsal horn
What lamina in the superficia dorsal horn do central process nociceptors synapse on
Lamina I/II or V
How do nociceptors activate receptors on sp neurons
nociceptors release glutamate and substance P to activate them
2nd order sp neurons send axons _________ of sp cd
COnTRALAERAL
Loss of pain and temp below level of lesion on contralateral side
lesion of anterolateral system
Lesion of anterolateral system is complete withing
2-3 segments below lesion
Where does the second neuron cross to other side
via the anterior commisure
Unilatreal anterolateral tract lesion results in
lose pain and temp on contralateral side
Bilateral anterolaterel tract lesion results in
loes pain and temp bilaterally
common type of bilatereal anterolateral lesion
Anterior cord syndrome
Common causes of anterior cord syndrome
disc herneations, bone frags, loss of blood supply
hole in center of sp cd
central cord syndrome
Causes of central cord syndrome
syringomyelia: cavity or cysts in center of sp cd from trauma, tumors, congential abnormatility
- -cervile sp cd is very flexible so you can get inside of it stressed out (often diving or falling)
Lesion cuts crossing axons of 2nd order neurons that are making their way to anterolateral tracts before they ascend rostrally
Central Cord syndrome
c. Deficiets of central cord syndrome
Bilateral loss of pain and temp
-small hole can spare dorsal columns and anterolateral tracts
What derms are affected with central cord sydrome
–affects only dermatomes of spinal level where lesion exsists.
(so if hole is C3-T4 you have loss of pin prick and temp but maintain jt pos and light touch and vibration)
Three major anterolateral paths all begin in
sp cd
Three major anterolatreal paths ascend…
adjacent to each other in anterolateral track and terminate in dif locations
Spinothalmic tract terminates in
thalamus
Spinoreticular tract terminates in
reticular formation (in medulla or pons)
Spinomesencephalic trct terminates in
mesencephalon (midbrain)
Most 2nd neurons termiante in
spinothalmic tract
this is our most prominent pain pathway
spinothalmic
spinothamic mediates ________ apsects of pain
discriminative
–location, intentisty, duration of stimulus
In thalamus, axons from body terminate in 2 nuclei:
Ventral Poserior lateral
Central lateral nucleus
The VPL is in the_____ and recieves___
thalamus
pain info from body
3rd order axons project to ______ from teh VPL
SI cortex (Areas 3b, 1, 2)
What is our priniciple relay nucleus for DISCRIMINITIVE pain infor from body
the VPL
VPL localized where noxius stimulus on body occurred and _____
how intense it is
it’s pain qualities
What localizes where noxious stimulus on body occured and how intense it is/pain quality
VPL in the spinothalmic tract
What two things have input into the VPL
spinothalmic and dorsal column/medial lemniscus
The Cental lateral nucleus is part of:
intralaminar nuclie
3rd order axons from CL project to:
many areas on cortex and limbic cortex (cingulate gyrus and hippocampus, amygdala)
involved in emotional suffering during chronic pain and memory of pain event
Central lateral nucleus
is the CL somatotopically organized
NO
a. Process nocireceptive info: begin crude pain and temp sensation, begin emotional suffering rxns
Thalamus
Thalamic nuclei will relay info to SI cortex: 3rd order neurons pass through_________ , corona radiata to SI cortex
posteior limb of internal capsule
CC lesions of thalamus would affect
way we process pain
2nd order axons terminates in reticular formation (in medulla and pons)
Spinoreticular tract
Reticular formation processing affects how:
we give attention to painful stimulus
Involved in emotional, arousal, attention, affective response to noxoius stimulus
spinoreticular tract
. 2nd order axons terminate in mesencephalon (midbrain) in superior colliculus and Periaqueductal Gray (PAG)~ tissue around cerebral aqueduct
Spinomesenphalic
Spinomesenphalic tract has 2nd order neourons that terminate here:
midbrain in superior colliculus and Periaquiductal gray (PAG)
Neourons in PAG do what
send axons back down spinal cord = descending contrl pathway
tract stimulates descending control to inhibit pain signals coming up
Spinomesenphalic
PAG and superior colliculus are located in
midbrain
Tract for discrimination
Spinothalmic (something sharp is in my left toe)
Tract for attention/arousal/affect
spinoreticular (ouch, that hurts)
Endogenous pain reliefe
Spinomesenphalic tract (that feels better)
Thalamic neurons from VPL project to
Somatorsensory cortex SI:
3b, 1, 2 and SII cortex
Primary somatosensory cortex (S1) postcentral gyrus parietal lobe
d. Broadmann areas 3, 1, and 2
e. arms and neck medial/// legs are lateral
part of limbic system
a. Processes emotional component of pain: Fear, anxiety, depression, anger, attention
Cingulate gyrus:
: Process info on interal, autonimic state of body (heart races, rapid breaths, dry mouth ,people w/ chronic stress can’t sleep)
Insular Cortex
Asymbolia for pain~ they can percieve the pain
Lesion insular cortex:
integrartes discriminitive, affective, emotional, cognitive components of pain
big PROCESSOR or INTEGRATOR of pain
Insular cortex
Neurons with Cell Bodies in PAG
1. Sends axons to a. Others send axons to
Raphe nuclei (medulla) ~ release Nepi Locus ceruleus (pons) release Seretoni
Raphe nuclei is located in:
releases:
medulla
Nepi
Locus ceruleis located in:
releases:
pons
seratonin
Neurons from Raphe nuclie or Locus cerules send axons to sp cd to
a. Synapse on \_\_\_\_\_\_\_\_\_\_ b. Suppresses transmission of
inhibitory interneurons or Spinothalmic tract neurons (inhibit)
ascending noxious info to thalamus and cortex
Why do we get referred pain?
visceral nocireceptors and somatic nocireceptors converge and synapse onto the same 2nd order spinothalmic tract neurons
a. Somatic stimuli occur frequently but visceral stimuli are infrequent b. Brain will interprest any spinothalmic tract impulses as pain from somatic tissue
