Physiology 8: Pain and Thermosensation Flashcards
pain in the viscera often refers to..
a somatic structure
nociceptors are what type of neuron?
primary sensory afferents
nociceptors are __ order neurons
first
how do nociceptors relay information to second order neurons?
by chemical synaptic transmission using neurotransmitters
where does transduction begin?
free nerve endings
name the 2 types of fibres that can be nociceptors?
A-delta fibres
C fibres
which type of nociceptor fibre is myelinated?
A-delta
which type of nociceptor fibre is for slow pain?
C fibre
which type of nociceptor fibre is for mechanical stimuli? ooes this fibre work fast or slow?
A-delta fibre
fast
how do thermal stimuli project to the CNS?
via depolarisation from an Na/Ca influx causing an AP
how do chemical stimuli cause a response?
chemicals activate specific receptors to cause a response
what neuro tracts are involved in the pain response?
spinothalamic
spinoreticular
some C fibres transmit pain info to the CNS via release of….
glutamate and peptides
some C fibres project pain by releasing…
pro-inflam mediators eg CGRP and substance P
what does substance P cause?
vasodilation
leakage of plasma proteins
histamine release
= NEUROGENIC INFLAM
what does CGRP do?
causes vasodilation
main symptoms of neurogenic inflam?
primary and secondary hyperalgesia and allodynia
peptides cause a fast EPSP T or F
F, cause a slow, prolonged EPSP
primary afferent cell bodies are located where?
dorsal root ganglia
where do the axons of primary afferents terminate?
dorsal horn of spinal cord
cells that receive input from alpha-beta fibres will provide sensory info of what function only?
proprioception
what types of neurones receive input from all 3 types of fibre?
wide dynamic range neurons
visceral afferents from nociceptors follow what pathway before entering the dorsal horn?
sympathetic
why do you get referred pain
some visceral and skin afferents converge on the same neurons at a given area and the brain thinks the visceral pain is coming from the skin afferent
heart dermatomes for referred pain?
T1-5
gallbladder dermatomes for referred pain?
C4
do nociceptive tracts use the anterolateral or ventromedial system?
anterolateral
which nociceptive tract is responsible for C fibres ie slow pain?
SRT
spinoreticular
spinothalamic tract is responsible for __ pain
STT (spinothalamic)
which tract is for pain perception?
STT
SRT is for which type of pain?
autonomic pain, arousal, emotional responses
