Pain pathways and central processing of pain Flashcards
Define pain
Sensory/emotional experience from potential/actual tissue damage, or described in terms of such damage
The difference between nociception and pain?
nociception = neural process pain = + psychological component
describe convergence
a single sensory neurone in the cns can receive inputs from multiple receptors
describe the different types of pain fibres
Aa FASTEST largest proprioception
Ab medium fast mechanical . 2nd biggest
Ag 3rd biggest. medium fast . pain and temp. sharp pain
C slowest unmyelinated . pain and temp. dull pain
how the ascending paths of touch and pain differ
touch (tactile) travels up same side until the medulla where it crosses over
pain crosses over immediately and ascends
what does the tactile path ascent in the brainstem as
medial lemniscus
describe:
sensory discriminative
emotional affective
SD- tells you if youve been hurt and where
EA - association of unpleasent emotions with nociceptive stimuli
What NT anatagonists are Ab fibres and C fibres sensitive to
Ab - glutamate NMDA
C - Glutamate and substance p NMDA + AMPA
what type of pain is C
slow burning - chemical and thermal
what do Ab fibres sense and where are they found
3+ 4 dorsal horn
describe placticity of pain
same stimulus lots of times gets more and more sensitive until = pain. ‘wind up’
Name some other effects of pain on the body and how they occur
orientation, respitation increases in changes in BP. branches of the SR tract . activated by brainstem
Describe somatosensory transduction
Membrane deformed Na+ and K+ channels open Receptor gen potential Local depolarisation of membrane AP propagated to CNS
Describe recruitment
Increased no of responsive receptors and fibres
Define allodynia
and hyperalgesia
Allodynia- non painful stimulus perceived as painful
Hyperalgesia- painful stimulus seems more painful
