Pain Flashcards
what is pain
an unpleasant sensory emotional experience associated with actual or potential tissue damage.
why is pain important
it promotes the avoidance of situations which may decrease biological fitness. it also promotes resting behaviour which can enhance recovery and can modify our behaviour to avoid further injury.
what is a nociceptor
a type of sensory receptor that detects pain. They have free nerve endings. they send signals to synapse in spinal cord which ascends to neurones within the brain
how do nociceptors reposed to painful stimuli
nociceptors = polymodal (can respond to multiple stimuli), for example intense pressure, stretching, heat, acids and damage.
what type of nociceptors does heat, acids and capsaicin (chilli) activate
vanillin receptors or TRP channels
what type of nociceptor does damage (e.g. cut) activate
purinergic receptor
what are the two pain pathways to the brain
- somatosensory cortex (via thalamus), encodes the sensory components and involves sensory discrimination (telling you where it hurts). 2. to the emotional cortex (via thalamus), not telling you where it hurts just that you’ve been hurt, encodes the emotional feelings of unpleasantness.
what are the different types of pain sensation process?
hyperalgesia, allodynia, peripheral sensation, central sensation
what is hyperalgesia
noxious stimuli produce exaggerated pain sensation to protect us from damaging the area further and allowing for appropriate healing
what is allodynia
refers to perception of pain in response to normally non-painful stimuli e.g. touching a burn. serves as a protective mechanism to prevent further damage
what is peripheral sensitisation
when tissues is damaged an inflammatory response occurs. peripheral sensitisation enhances the transmission of pain signals from site of damage to CNS
what is central sensitisation
refers to neuroplastic changes that occur in spinal cord. central sensitisation can cause brain to perceive pain more intensely or persistently even after initial injury as healed. can contribute to development of chronic pain.
what neuropeptides are released during inflammatory response. what does it trigger
neuropeptides such as substance P and CGRP are released from nociceptor neurones. which triggers vasodiliatoin (dilation of blood vessels, increase BP), plasma extravasation, activation of mast cells & neutrophils.
