Pain and Thermosensation Flashcards
Most analgesics that are normally used to treat pain have limited use in pathological pain, however what are some options?
Atypical analgesics e.g. antidepressants, anticonvulsants and local anaesthetics
Nociceptors are usually activated by what?
Intense stimuli (thermal, mechanical or chemical) that are noxious
What order neurones are nociceptors?
First order
Pain is only felt when?
Once nociceptors have passed on their information to the CNS
Nociceptors are what type of neurones? They have what type of nerve ending?
Pseudounipolar / free nerve endings
Complete the sentence: nociceptive input causes ? of the free nerve ending which produces an ? which progresses along the soma of the neurone and causes the release of ?
Depolarisation / action potential / neurotransmitter
Activation of the first order neurone (nociceptor) should only respond to intense, noxious stimuli. What happens if these are activated without stimuli?
Hyperalgesia/allodynia
What type of nerve fibres are nociceptors?
A delta and C
What are the different types of stimuli that can activate the peripheral terminal of polymodal nociceptors?
Chemical, mechanical and thermal
The soma of the first order neurone (nociceptor) is found where?
Either in the dorsal root ganglion or the trigeminal ganglion
What happens when fibres from a nociceptor reach the dorsal horn of the spinal cord?
They synapse and cross over
After a nociceptor synapses with its second order neurone in the spinal cord, the axon of the second order neurone then carries the information up which spinal cord tracts to the CNS?
Spinothalamic and spinoreticulothalamic
Peptidergic polymodal nociceptors are a subset of which type of nociceptor fibre?
C-fibres
Complete the sentence: afferent aspects of nociceptors transmit nociceptive information to the CNS via the release of ? and ?, within the ? horn of the spinal cord
Glutamate and peptides / dorsal
Describe visceral pain?
Tends to be poorly localised and have a dull, aching character
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 known as?
Referred pain
Visceral pain that is perceived at a distant site from the affected organ is often associated with what features?
Nausea, vomiting, sweating and pallor
Referred pain around the umbilicus can come from where?
Appendix
Referred pain around the epigastric region can come from where?
Stomach/pancreas
Referred pain down the arm and in the jaw can come from where?
Heart
Referred pain to the shoulders can come from where?
Liver/diaphragm/gallbladder
Viscerosomatic pain is usually sharp and well localised - what causes this?
When inflammatory exudate from a diseased organ contacts a somatic structure
Pain evoked by activity in nociceptors can be reduced by simultaneous activity in where?
Low threshold mechanoreceptors (A beta fibres)
