Head and Face Pain Neurophysiology Flashcards
(21 cards)
What is Nociception?
The activity in a neural structure capable of leading to or contributing to a sensation of pain.
What are the four steps for the Nociceptive pathway?
- Transduction
- Transmission
- Modulation
- Perception
What is Transduction?
Primary Afferent Nociceptor activation from noxious stimulus
What is Transmission?
The coded message traveling from the Primary Afferent Nociceptor into the dorsal horn of the spinal cord
What is Modulation?
The change or attenuation of a nociceptive stimulus in the grey matter of the spinal cord
What is perception?
The coded message traveling from the dorsal horn to the contralateral cortex.
What are pain r/c’s classified as?
Free nerve endings that are slowly adapting with a high threshold.
What are the types of free nerve endings?
- Mechanical
- Thermal
- Polymodal
What are mechanical free nerve endings?
Receptors that respond to sharp penetration. They are faster conducting and more localized.
What are thermal free nerve endings?
Receptors that are activated by temperature extremes.
What are polymodal free nerve endings?
Receptors that are activated by mechanical, chemical, and thermal stimuli.
Deep burning with poor localization.
Ex: Lactate in Muscles
What are the Nociceptive fiber types?
A-delta and C fibers
What are A-delta fibers?
Thinly Myelinated Smaller Diameter Slow Conducting (5-30m/s) Pricking Pain More Accurately Localized
What are C fibers?
Unmyelinated Smaller Diameter Slow Conducting (0.25-0.35 m/s) Burning Poorly Localized
What is released during the localized effects of pain stimuli?
There is a release of Substance P, Calcitonin, CGRP, Neurokinase A, and other inflammatory mediators.
What do the release of inflammatory markers during pain stimulation result in?
Resulting in vasodilation, transport of plasma, and contraction of smooth muscles.
What do the localized effects of pain stimuli play a role in?
Peripheral sensitization of tissue along with other sympathetic responses
Describe the Pain Pathway from Pain to WDRN with Stress.
Stress simulates the adrenals to produce cortisol and NE/E, sensitizing the C-fiber
Pain activates C-fibers from the nociceptor act on NMDA r/c’s to stimulate the WDRN.
Describe the Pain Pathway from WDRN to PMRF.
Activation of the WDRN stimulates the cortex, which sends collaterals to the PMRF.
What are the 4 functions of the PMRF?
- Decrease the IML bilaterally.
- Decrease the sensitivity to pain.
- Increase global muscle tone
- Decrease tone of the anterior muscles above T6 and the posterior muscles below T6.
Describe the pain pathway from the LDA to the Cortex and PMRF.
LDA stimulate the AMPA r/c on WDRN nuclei directly and indirectly through interneurons. They also stimulate the cerebellum, which sends stimulatory neurons to both the Cortex and the PMRF.
