Pain physiology Flashcards
What are the processes of pain?
Transduction
Transmission
Modulation
Perception
How does pain work?
nociceptors (first order neurones) relay information to second order neurones in the CNS by chemical synaptic transmission
second order neurones ascend the spinal cord in the anterolateral system
sensory information is relayed from the thalamus through third order neurones to the primary sensory cortex
What are nociceptors?
afferent neurones that innervate peripheral tissues - achieved by noxious stimuli
Glutamate and peptides
What makes up the anterolateral system?
spinothalamic tract - pain perception
spinoreticular tract - automatic responses to pain and emotion
What are the types of nociceptors?
Adelta fibres
C fibres
Describe Adelta fibres?
mechanical/thermal receptors that are thinly myelinated and mediate FIRST/FAST pain
Describe C fibres?
unmyelinated fibres that respond to all noxious stimuli and respond to SECOND/SLOW pain
Describe Nociceptive pain?
only produced by intense stimulation by noxious stimuli
functions as an early warning physiological protective system to detect and avoid noxious (damaging) stimuli
Describe Inflammatory pain?
caused by activation of the immune system by tissue injury or infection and the subsequent mediators at the site of inflammation
- pain discourages physical contact with affected part and movement of it
What are the two types of Pathological pain?
Neuropathic and Dysfunctional
Describe Pathological Neuropathic pain?
damage to neural tissue which is percieved as burning, shooting, numbness and pins and needles
Describe Pathological Dysfunctional pain?
no identifyable damage or inflammation
often treated by antidepressants
What is Referred pain?
caused by convergance of noiceptive visceral and skin afferents upon the same spinothalamic neurons and the same spinal level
