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Flashcards in Pain Deck (19):

What are the two classes of pain sensation

adaptive, protective pain
- nociceptive pain
- Inflammatory pain
Maladaptive, pathological pain
- neuropathic pain
- functional pain syndrome


What are the responses to nociceptor activation?

pain - higher order cortical process -> learn about things that might hurt us
autonomic responses
withdrawal reflex - spinal cord reflex


What are the 2 nociceptor fibre types?

C Fibres and Adelta fibres


What are the characteristics of C fibres? where do they project?

fine diameter and NO myelin ("See them bc their naked"), dorsal rexed laminar (regions 1 & 2) of the dorsal horn -> slower burning/throbbing pain.


What kind of fibre types are the cutaneous (meissner, etc) mechanoreceptors?

A-beta fibres


What are the features of the A-delta fibres - what info do they carry?

myelinated, fine diameter, med-fast transmission to both dorsal and ventral rexed lamina of the dorsal horn (regions 1 and 5) - initial SHARP pain


What happens to receptor firing when stimuli is removed from touch receptors vs nociceptors?

touch = stops firing, nociceptors continue to fire if tissue has been damaged


Where are Adelta and C fibre nociceptors found?

hairy skin = both, glabrous skin only has C fibres


What two things are altered in Inflammatory pain?

altered pain sensitivity & spontaneous pain


Describe the process of peripheral sensitisation



What is hyperalgesia?

an increased response to a normally painful stimulus -> accentuated feelings of pain -> change in stimulus intensity


What is allodynia?

a painful response to a normally innocuous stimulus -> change in threshold


What is central sensitisation?



What is neuropathic pain? What happens in peripheral neuropathic pain?

pain due to a neural lesion and damage to the somatosensory system eg brachial plexus avulsion, strokes or MS.
peripheral: - fibres generate pain signals without stimulation


What is dysfunctional pain?

pain which is due to no identifiable pathology ->eg migraine, fibromyalgia


What is the descending pathway that modulates pain?

periaquaductal grey, rostroventral medulla


How does affective responses (emotional state) influence pain perception?

natural threat/stimulus (ie cat for a mouse) causes hypoalgesia as part of the fear response -> amygdala sends signals to the PAG. Expectations of pain can increase pain sensations felt


the spinoparabrachial tract transmits signs from nociceptors to where?

limbic centre -> emotional/aversive perception


What is secondary hyperalgesia? how does it occur?

expansion of region of sensitivity into areas which were not physically damaged due to Central sensitization