Slow pain transmission by C fibre nociceptors Flashcards
What are the 3 pathways that project into the brain, in slow pain transmission?
spinoreticular, spinolimbic, spinomesencephalic pathways
What structure of the nociceptor detects the noxious stimulus, and what order neuron is this nociceptor?
Free nerve endings of the first-order nociceptor detect noxious stimulus
What occurs at the first relay site of slow pain transmission, and where does it happen?
In dorsal horn, the proximal/central axon of first-order nociceptor terminates and nociceptive signal is transmitted to laminae I and II second-order neurons/interneurons via synaptic transmission
After the first-order nociceptor has detected the noxious stimulus, how is the signal transmitted to the spinal cord?
Signal transmitted down peripheral axon of the nociceptor to sensory ganglion, then down central axon which soon enters dorsal horn of the spinal nerve in the spinal cord
What are the laminae I-VI of the dorsal horn, and why are they labelled in that order?
Neuronal cell layers that receive different primary afferent sensory fibres
labelled I-VI in dorsal-ventral root direction
In which 2 laminae of the dorsal horn are C fibre nociceptors received for slow pain transmission?
Lamina I and II
Why are the second-order neurons also called interneurons in slow pain transmission?
The second-neurons travel up 3 different tracts to the brain
What 2 midline areas do interneurons travel to up the spinomesencephalic tract, in slow pain transmission, and what is the role of these 2 brain regions?
Superior colliculus controls visual reflexes eg. turning head and eyes to look at body region where noxious stimulus was detected
PAG: part of descending nociceptive system
What area do interneurons travel to up the spinoreticular tract, in slow pain transmission, and what is the role of this brain region?
Brainstem reticular formation, which controls sleep cycle, arousal, and attention
In slow pain transmission, what brain region do axons project to from the brainstem reticular formation?
Axons from here also project to intralaminar thalamic nuclei
In slow pain transmission, which 2 brain regions do axons project to from the intralaminar thalamic nuclei, and what do these brain regions both control?
Anterior cingulate cortex and insular, where unpleasantness of pain is processed
What areas do interneurons travel to up the spinolimbic tract, in slow pain transmission?
Amygdala and other limbic structures
In slow pain transmission, which brain regions do axons project to from the amygdala and other limbic structures, and what do these brain regions both control?
Other cortices that control emotions and cognitions, such as feeling anxiety and fear
