Pain 💘 Flashcards
Nociception
The neural processes of detecting encoding and processing noxious stimuli, a physiological response
(Being physically in pain whereas term pain is subjective )
Different types of pain
Vascd
Visceral (organs of thorax and abdominal cavity affected) Superficial (skin) Deep (inside body ) Acute (resolves when injury heals) Chronic (long lasting poorly treatable )
Types of nociceptors
Thermal (temp) Mecahanical (pressure or deformation) Chemical (spicy food eg) Polymodal (all of above most common) Sleeping (activated by inflammation)
First pain
Fast sharp short
A delta fiber
Easily localized
Mechanical or thermal
Second pain
Slow dull aching burning
C fibres
Poorly localised
Long polymodal nociceptors
Transduction of pain
Receptors activated causing Receptor potential which depolarizers membrane
Na channels open generating action potential
Cell bodies in dorsal root ganglion
So enters spinal cord via dorsal horn
Ca channels cause neurotransmitter release
Second order neurons in spinal cord send signals up to brain
Termination of primary afferents
a delta and c fibres enter dorsal horn via drg
Innervste neurons in laminae 1&2
Second order take to laminae 4-6
Axons of second order cross midline and go to brain
Spinothalamic pathway
Sensory gross at spinal cords level and ascend on opposite side along spinothalamic tract
Info related via medulla to thalamus to somatosensory cortex
In somatosensory pathway it switched to opposite side in Medulla (pain in spinal cord and spine)
Referred pain
When u feel pain somewhere but it’s actually somewhere else
Phantom limb pain
Sensation that missing limb still attached
Gate theory
Coactivation of Aa/ betA and c fibres suppresses c fibres so pain reduced
Eg rubbing knee after falling
Pain management
Opioids
Morphine sulphate
Diamorphine
Nalodone receptor agonists reverses effects
