Exam 3 - Lecture 3 Flashcards
Why don’t arteries collapse?
Arteries have a high internal pressure and it would take a massive amount of ICP to collapse those.
Are 2nd order neurons in slow pain myelinated or not myelinated?
may or may not be myelinated
Are 2nd order neurons in fast pain myelinated or not myelinated?
Almost always myelinated
Tips of nociceptors are sensitive to 2 things
damage and chemicals (multiple as stated before)
Cell body of nociceptor is in:
dorsal root ganglia
What pathway is right next to nociceptor?
DCML pressure sensor considered a neighboring pathway
Nociceptors can connect to which lamina?
Fast: Lamina I
Slow: II, III, V
Where does lateral inhibition happen?
In dorsal horn or in periphery
Metabotropic receptors in ascending pain pathway are typically found where?
In the brain
Are ionotropic and metabotropic receptors in pain pathway excitatory or inhibitory?
Excitatory
In DIC, the 3rd order neuron secretes enkephalins and they bind to receptors in what areas?
periphery right outside cord and in the lamina
Enkephalin receptors are what type of receptors? what are they also called?
GPCRs; Opiate receptors
Enkephalin Receptors are functionally linked to:
Potassium channels
When opiates hit enkephalin receptors, it allows __________ to open. Results in what?
Potassium channels; to open and leave cell, making the cell more negative/difficult to excited.
There are opiate receptors on what part?
Both pre and post synaptic of pain pathway
What other receptors are on synapse in pain pathway?
Alpha-2 receptors
What do alpha-2 receptors do when an agonist binds to them?
Open up potassium channels.
What receptors do alpha-2 agonist drugs affect and where?
Both pre and post synapse/at 1st order nociceptor and 2nd order transmission neuron.
Opiate receptors and alpha-2 receptors both increase:
Cell wall permeability to potassium, not sure if theyre the same K+ channels or not.
Alpha-2 Agonists mentioned in lecture in order of specificity weakest to strongest
Xylazine, Clonidine, Precedex
What alpha-2 agonist mentioned also ends up being an alpha-1 agonist?
Xylazine
Why are alpha-2 agonist useful?
Just pain suppression/relaxation of CNS without getting high upstairs
Alpha-2 receptors are located where
all over CNS, but our focus is at the ascending pain pathway.
What drug do people abuse papa talked about? And what does the media call it?
Xylazine; horse tranquilizer
Volatile anesthetics effect on pain pathway
Suppress activity throughout nervous system, increase potassium conductance at pain synapse.
Potassium will always be _______ in this class.
Leaving the cell.
Cox-2 is expressed in:
1st and 2nd order pain neurons
More pain we have, the more ___ expressed.
Cox-2
COX-2 produces _________ which interact with __________. Which neurons?
Prostaglandins; prostaglandins receptors; 1st and 2nd order transmission neurons (ascending)
How do prostaglandins increase pain?
Increase sensitivity to painful things/amount of action potentials sent up ascending pain pathway.
Doesnt actually fire AP itself.
iNOS and what does it do
Nitric oxide synthase; increases painful stimuli sensitivity in the synapse
What supplement can help with chronic pain? Possible negative side effect?
Magnesium via blocking NDMA-r, but can cause upset stomach.
Do calcium levels impact pain like mag?
No.
4 spinal reflex pathways
Stretch, tendon, withdrawal, crossed extensor reflex
Which 2 spinal reflex pathways are responses to pain?
Withdrawal and Crossed extensor reflexes
Which 2 spinal reflex pathways are stretch sensors for muscles?
Stretch and tendon reflexes
Where are reflex sensors located?
Out in periphery, may involve pain sensors and tension receptors.
Where are tension receptors found?
Imbedded in skeletal muscles and/or tendons that can sense tension.
Reflexes must have ____ components. What are they?
2; sensory and motor
How do sensory and motor neurons talk to each other in reflexes?
Direct synapses in the grey matter of spinal cord.
Or via interneurons, can either be excitatory or inhibitory.
A “bridge” between motor and sensory neurons in reflexes
Interneurons
We may use _______ interneurons depending on complexity of reflex.
1 or multiple.
Afferent information
periphery to CNS (Sensory)
Efferent information
CNS to periphery (Motor)
In order for reflexes to occur on both sides of the body, the cross-over of communication happens via
Interneurons in the spinal cord, there are no direct pathways.
Stretch reflex is the most ______ reflex.
Simple