Flashcards in Symposium 8: Pain Deck (15):
What is nociception?
The sensory process that provides the signals that trigger pain.
What is pain?
The feeling or perception of irritating, sore, stinging, aching, throbbing, miserable, or unbearable sensations arising from a part of the body.
Where are nociceptors found?
In the periphery as simple free nerve endings
What substances are released upon tissue damage?
Prostaglandins, bradykinin and histamine that can sensitize peripheral nociceptors and induce hyperalgesia.
What is substance P?
Acts on mast cells and causes degranulation. Also causes blood vessel dilatation.
What is the function of prostaglandin?
Doesn't have a receptor on nociceptor, but sensitises it making signal transduction more complex.
What is the function of bradykinin?
Has a receptor on nociceptor.
Which nociceptors only respond to one modality?
Mechanical: respond to strong pressure.
Thermal: respond to burning heat / extreme cold.
Chemical: respond to histamine or other chemicals
In what type of nerve fibres does nociception take place?
Free nerve endings of unmyelinated ‘C’ fibres and thinly myelinated ‘Ad’ fibres.
What kind of fibres do thermal and mechanical nociceptors have?
What kind of fibres do polymodal nociceptors have?
What is the conduction speed of Ad fibres?
What is the conduction speed of C fibres?
What is 'first pain'?
- Fast A-delta fibres
- Sharp or prickling
- Easily localised
- Occurs rapidly
- Short duration
- Mechanical or thermal nociceptors