Pain Flashcards
Where does visceral pain originate from?
Nociceptors covering tissues or walls of hollow organs
The brain interprets nociceptive information arising from the viscera as originating from an area of skin that may be distant to the internal organ. What is this describing?
Referred pain
Acute pain vs chronic pain - which type of pain serves a useful purpose?
Acute pain - protective function as it signals there has been tissue damage
What are the 3 forms of pain?
Nociceptive pain
Inflammatory pain
Pathological pain
Which type of pain is being described: an appropriate physiologic response to painful stimuli
Nociceptive pain
Nociceptive pain is short lived / long lived?
Short lived
Nociceptive pain - when are nociceptors normally activated?
Activated by intense stimuli from peripheral tissues that are noxious
Nociceptors are second order neurones. True or false ?
False
- first order neurones
Nociceptive pain - where are second order neurones located?
In the CNS
Nociceptive pain - what is the primary transmitter?
Glutamate
Nociceptive pain - what are the 2 types of glutamate receptor
AMPA receptors
NMDA receptors
AMPA receptors cause very fast/slow depolarisation?
Fast
Nociceptor (First order neurone) enters the Ventral/Dorsal horn of the spinal cord?
Dorsal horn of SC
Which ascending tract does pain travel in?
Spinothalamic
Name 2 subtypes of nociceptor?
A-delta fibres
C fibres
Which nociceptor fibres mediate first/fast pain?
A-delta fibres
All nociceptor fibres are myelinated. True or false?
False
- A-delta = myelinated
- C fibres = un-myelinated
Which nociceptor fibres mediate second/slow pain?
C fibres
Inflammatory pain - function
Assists in healing
Which peptides are released in neurogenic inflammation?
Substance P
CGRP
Neurogenic inflammation - what does substance P cause?
Vasodilation
Release of histamine from mast cells
Sensitisation of surrounding nociceptors
Neurogenic inflammation - what does CGRP cause?
Vasodilation
Pathological pain has no physiological purpose. true or false?
True
Neuropathic pain - description of pain
Burning Shooting Tingling Sensitivity Allodynia Hyperalgesia
What is allodynia
Perception of pain even if the stimulus is non painful
What is hyperalgesia
More pain than expected from a painful stimulus
Neuropathic pain - causes
Shingles Surgery Trauma Diabetic neuropathy Amputation Many of unknown origin
How is neuropathic pain managed
Antidepressants (eg amitryptiline) Anti-convulsants Local anaesthetics (lignocaine)
How is it possible for pain evoked by activity in nociceptors (C- and Adelta- fibres) to be reduced?
Due to simultaneous activity in low threshold mechanoreceptors (A-beta fibres)
When you hurt your knee and rub it to make it feel better, what does this activate?
Activates Abeta fibres