Flashcards in Pain Deck (21)
What is nociception?
the sensation of pain before the cortical stage
It's purely a sensory process
Why do we feel pain?
it's a protective mechanism that avoids further damage.
There are spinal reflexes in place to withdraw from source of pain.
C fibres are the ______ fibres. It takes about _____ second to transmit signal to _______ . A-delta fibres are ______, and it only ______ second to transmit signal to ______
Pain fibres have ______ threshold and usually have ______ signal even after stimulus
dorsal horn has many laminae, which laminae do C fibres and A-delta fibres occupy
section i or ii for C fibres
A-delta fibres to i and V
T/F A delta fibres are found on glabrous skin
False, only C fibres are on glabrous skin
What is inflammatory pain
pain associated with release of inflammatory mediators which changes receptor sensitivity
what does capsaicin bind to? What else does the receptor respond to?
TRPV1, which also responds to heat, protein
What happens when TRPV1 is activated?
allow Na and Ca in to depolarise the cell
What determines the kind of nociceptor
the mixture of channels on the nocicpetor
What is hyperalgesia? What is an example?
an increased response to a normally painful stimulus
what is allodynia?
painful response to a normally innocuous stimulus
What are the two types of neuropathic pain?
neuropathic pain - damage to nerve
dysfunctional pain - no neural lesion/inflammation, spontaneous pain
What are some common causes of maladaptive pain?
Can you tell if someone is in pain with imaging?
No, many areas such as PFC, S1 are activated during pain sensation, but you can't tell which cell is driving pain response
What are the two pathways of pain processing
sensory pathway and emotional part of pain in the cingulate
how do most analgesic drugs work
there is a descending pathway that inhibits spinal nociceptive transmission through PAG. Most drugs work on this pathway to interfere with nociception
What is hypoalgesia associated with?
fear and anxiety, so they can block pain
what is the basis of placebo
the expectation of reducing pain will actually reduce pain
What is an evidence showing that placebo works on the descending PAG pathway?
placebo analgesia is reduced or prevented by opioid antagonist, so there are substance released by higher cortex when taking placebo