Pain Pathways Flashcards
What are the 4 primary afferent fibres?
Aα, Aβ,Aδ and C fibres.
In order from biggest diameter, rank the primary afferent fibres.
Aa, Ab, Ad, C
In order or speed of transmission, rank the primary afferent fibres.
Aα, Aβ,Aδ and C fibres.
What does each fibre detect?
Aa - proprioception.
Aβ - Mechanoception.
Aδ - Pain and temp.
C - Pain and temp.
Intensity of pain is encoded by what?
The size of responding receptor population and numbers of fibres activated.
What is recruitment?
An increase in the number of responding receptor population and number of fibres activated.
Where do pain tracts decussate?
Spinal cord.
Where do tactile tracts decussate?
Medulla.
Central branches of touch afferent fibres ascend where? And synapse where?
Dorsal columns. Synapse in dorsal column nuclei.
In the thalamus where do the tactile tracts synapse?
VPM and VPL nuclei.
What laminae are the main site of nociceptor afferent termination?
1 and 2.
2nd order neurons in the spinal cord project to the thalamus in what tract?
Spinothalamic.
What are the 3 theories of pain?
Specificity theory: pain is a symptom of disease. Does not necessarily correlate with disease activity.
Gate control theory: gate system in the spinal cord that can be influenced by the brain.
Neuromatrix theory: processing from a distributed neural network. Pain is a psychological stressor and this can influence pain response.
Pain is modulated by what 4 things?
Attention, expectations, emotion, past experience.
Does memory for pain decrease or increase over time?
Decrease.
