pain Flashcards
Define pain.
Pain is an unpleasant sensory and emotional experience, associated with acute tissue damage or described in terms of such damage.
What is the source of nociceptive pain?
Direct insult to tissue
-thermal, mechanical, chemical
Nociceptors are ____polar neurons
pseudo-unipolar
Nociceptive pain initiates the _____ reflex
withdrawal
Hypersensitisation
and allodynia results from nociceptive pain (T/F)
False
Inflammatory pain
What is the purpose of inflammatory pain?
Assists healing of damaged tissue
What are the 2 types of pathological pain?
neuropathic pain
dysfunctional pain
Damage to peripheral neurone causes _____ pain
neuropathic pain
Abnormal processing of sensory input in the CNS results in _____ pain
dysfunctional
What are the subtypes of nociceptor neurons?
A-delta-fibres
C-fibres
_____ are mechanical/thermal nociceptors. They mediate fast pain.
A-delta fibres
_____ are unmyelinated
C-fibres
These fibres respond to all noxious stimuli - they are polymodal.
C-fibres
Burning, throbbing, cramping and aching is mediated by ____ fibres
C-fibres (polymodal)
-poorly localised
Stabbing, pricking, lancinating pain are mediated by…
A-delta-fibres
-precisely localised
What is the temperature threshold recognised by A-delta Type I fibres?
53oC
A-delta Type II fibres are activated at ___oC
43oC
What are the mechanisms contributing to hyperalgesia and allodenia induced by C-fibres?
- Increased excitability of secondary neurons
2. Neurogenic Inflammation: release of pro-inflammatory mediators at peripheral terminal of C-fibres (substance P, CGRP)
What does substance P do in tissue?
Induces inflammation
-vasodilatation, mast cell degranulation, nociceptor sensitization
Stimuli in the nociceptive nerve terminal induce a _______ _______by opening ion channels. This is proportional to stimulus intensity.
Generator Potential
The frequency of action potentials is at the nociceptive neurone is proportional to the ….
amplitude of the Generator potential
Where does the Primary Afferent Nociceptor synapse with the secondary order neurone? What is the neutrotransimtter?
Dorsal horn of spine
Glutamate
What neurons, found in the dorsal horn, receive input from C-fibres, A-delta-fibres and A-beta-fibres?
Wide Dynamic Range (WDR) neurons
Spinothalamic tract (STT) signals the ____ of pain
location
Spinoreticular tract (SRT) signals the ______ of pain
severity
