pain and thermoregulation Flashcards
Specific peripheral primary sensory afferent neurones?
nociceptors
where are cell bodies of nociceptors found?
dorsal root ganglia or trigeminal root ganglia
first order neurones that relay information to second order neurones in the CNS by chemical synaptic transmission
nociceptors
thinly myelinated nociceptors?
aD fibres
nociceptors that are unmyelinated?
c fibres
Mediate ‘first’, or fast, pain
a delta fibres (myelinated so faster)
Mediate ‘second’, or slow, pain
c fibres
sub classification of a delta fibres?
Type I (HTM: High Threshold Mechanoreceptors) - require strong mechanical stimuli for activation, activated by noxious heat (threshold > 53ºC).
Type II - respond to noxious mechanical stimuli and also to noxious heat (threshold 43ºC – 47ºC), sensitive to capsaicin.
sub classification of c fibres?
CMH CM CH CMH m= mechano, H = heat
responsive to environmental stimuli
site of release of molecules that influence local tissue environment
peripheral terminal
not responsive to environmental stimuli
Site of Ca2+-dependent transmitter release (e.g. glutamate, neuropeptides
central terminal
where are primary afferent cell bodies located?
dorsal root glanglia (trigeminal root glanglia in face)
pathway of V1, V2 and V3?
Soma of sensory neurones are located in the trigeminal sensory ganglion
Central terminals of the trigeminal nerve synapse upon second order neurones in the chief sensory nucleus (general tactile stimuli), or spinal nucleus (pain, temperature information) which in turn decussate and project (via the trigeminal lemniscus) to the ventroposteriomedial (VPM) nucleus of the thalamus
Neurotransmission Between the Primary Afferent and Second Order Neurone in the Dorsal Horn. what is the main neurotransmitter?
glutamate (pain in arse)
what does glutamate activate
NMDA and AMPA receptors
