Pain Flashcards
3 types of pain?
physiological nociception, pathophysiological nociception, neuropathic nociception
cause of physiological nociception?
tissue-damaging stimuli
cause of pathophysiological nociception?
underlying disease
cause of neuropathic nociception?
damage of nerves (abnormal since not relevant for hazard perception)
2 location classification of pain?
somatic, visceral
where do you feel somatic pain?
“outside” skin, mucles
where do you feel visceral pain?
inside organs
2 types of pain classification depending on duration?
chronic, acute
what is direct nociceptor activation?
transient receptor potential channels (TRP) directly activating nociceptor
what is indirect nociceptor activation?
intermediate molecules (eg. ATP) that activate channels that then activate nociceptor
function of thermoreceptors?
sense cold/warmth
2 types of nerve fibers?
C fibers, Adelta
describe C fibers
small, unmyelinated = slower speed signal
describe Adelta fibers
small, myelinated = faster speed signal
describe how pain gets perceived
signal travels through
- spinal cord
- thalamus: senses and identifies type of pain
- somatosensory cortex: perceives pain
- medial thalamus sends signal to limbic structures -> emotional/aversive response to pain
- amygdala: forms memory of the pain (involve emotional reaction)
factors determining intensity of pain?
frequency of action potentials in nociceptors & fibers
function of endogenous analgesic system?
reduces pain perception to allow for survival
what’s central sensitization?
signal translation in CNS increases nociceptor responsiveness & sensitivity to pain
what are opioid peptides?
small molecules that act like neurotransmitters to reduce pain perception (eg. eukephalin)
How does eukephalin work to reduce pain perception?
spinal interneurons release eukephalin at the synapse of receptor neurons in the dorsal horn, inhibiting substance P release -> less pain impulses received by brain
How do opioids work to mimick enkephalin?
dec. calcium influx into nociceptor -> dec. duration of action potential in nociceptor (due to less Ca ion channels letting Ca in) -> hyperpolarizes neurons of dorsal horn -> dec. pain perception
hyperalgesia
painful stimulus triggers inc. pain response
allodynia
pain after something normally not painful
paresthesia
distorted sensation w/ no apparent physical cause
dysesthesia
abnormal sensation, related to CNS