N11 Pain And Crps Flashcards
Sensory-discriminative pathway
the spinothalamic tract carries fast/first pain (A-delta) that is precisely localizable and discriminative. Projects to S1 cortex
Affective-Motivational pathway
information from C fibers (slow/2nd pain) projected to multiple regions - including brainsetm structures, deep cerebral nuclei (e.g. amygdala), and parts of the limbic lobe (anterior cingulate gyrus)
Spinoreticular tract
affective motivational pathway
slow/second pain, temp, crude touch (C fibers)
- Protopathic (non-discriminative, poorly localizable)
- projects to wide-spread cortex and limbic system
Spinomesencephalic tract
All C fibers
does not reach cortex - Projection into superior colliculus.
- projects to periaqueductal gray - (descending fibers for endogenous gate control of pain)
Referred pain pathway
some** visceral sensory primary afferent that do project to conscious areas REUSE pre-existing projection neurons that represent elements of the body wall.
Referred pain is a consequence of what?
The convergence of visceral and body wall primary afferents on projection neurons in the dorsal horn of the spinal cord.
Pain matrix: ‘tip of the knife feels sharp on index finger”
AB fibers to the S1 via DC-ML
Pain matrix: ‘getting lightly prodded by this knife kind of hurts my finger’
A-delta fibers to SI via STT
pain matrix: “I’ve now got a laceration on my index finger”
A-delta fibers to SI via STT
pain matrix: “ouch, that really hurt! and it’s still hurting! and I don’t like it!”
C fibers to limbic system via Spinoreticular tract
Pain matrix: “We should do something about this cut finger situation”
C fibers to midbrain structures via Spinomesencephalic tract
What do nociceptive neurons contribute to the inflammatory soup??
Substance P and CGRP
What is the Axon reflex?
neurogenic inflammation -
1. sufficient stim on branch triggers ap
2. AP fires up the axon
3-4 . AP cont up the peripheral process of sensory neuron
5. axon collaterals to sens ending that weren’t triggered are not in their refractory period, so the ap travels down them as well TOWARDS the receptive ending.
6-9. Activation of nociceptors leads to the release of Sub P and Calcitonin gene-related peptide (CGRP)
Action of Substance P (SP)
acts on mast cells to cause degranulation and histamine release (swelling)
- SP produces plasma extravasation
Action of CGRP
produces dilation of peripheral blood vessels
