Nociceptive Pain Flashcards
What is nociception?
The process by which pain is registered via free nerve endings
What is a nociceptor?
A sensory neuron with a free nerve ending that detects pain
Which nociceptor is fast, myelinated and unimodel?
A delta
Which nociceptor is slow, unmyelinated and polymodel?
C fibre
Which fibre competes with the pain ones and is activated by rubbing/pressure/tactile stimulus?
A beta
What is the first order neuron in pain?
Nociceptor to spinal cord
What is the second neuron in pain?
Spinothalamic tract to thalamus
What is the third order neuron in pain?
Thalamocortical projections to the cortex
What area of the brain is responsible for making pain unpleasant?
Insula and anterior cingulate
What part of the brain helps localise the pain
Primary somatosensory cortex
How is pain modulated?
Descending pathways
Which areas of the brain are repsonsible for pain modulation via the descending tracts and via what NT?
Periaquadutal grey - enkephalins
Locus ceruleus - noradrenaline
Raphe nucleii - serotonin
How do they descending tracts work?
Serotonin and noradrenaline cause enkephalins to be released by interneuron
PAG causes enkephalin release and serotonin release from RN .
This causes post synaptic hyperpolarisation AND shut down activity between the post and presynaptic membrane
What external source increases the action of the descending pathways?
Opiates
How does inflammation cause pain?
It causes the release of prostaglandins and histamine which trigger the nociceptors
