Exam 3 Content Flashcards
DCML
Dorsal Column Medial Lemniscus
what type of fibers does the DCML use ?
FAST
All the A’s
A-delta
A-Gamma
A-Beta
A-alpha
Where is the DCML located and what are its sub-tracts?
Dorsal Horn
Fasciculus Gracilis
Fasciculus Cuneatus
Where does the Fasciculus Gracilis originate from ?
Lower body afferent sensory information
Where does the Fasciculus Cuneatus originate from ?
Upper body/extremity afferent sensory information
Where does the DCML pass through and in what direction ?
Afferent information through the medial lemniscus in the brain
Is the Medial Lemniscus second or third order neuron of the DCML?
SECOND
What is the Ventrobasal complex?
A portion of the Thalamus that DCML pathway signals pass through , to the internal capsule , then parietal lobe.
DCML pathway relays what kind of senses?
Touch
Pressure
And vibrations
What is a Homunculus ?
A anatomical pictograph of the different portions of the parietal lobe that processes information from different portions of the body
Proportions are equal to amount of sensors
low density = low sensors
High density = high sensors
Where is the Internal Capsule and which pathway uses it?
Internal Capsule is situated between the thalamus and parietal lobe
DCML uses it to relay signals to the parietal lobe
Major Relay center for pain/pressure information in the brain ?
THALAMUS
How many categories of spinal tracts are there?
5
What is the name of the grey matter in the spinal cord ?
REXED’s LAMINAE
How many subdivisions are there in REXED’s laminae
9 throughout the grey matter
1 central canal (laminae 10)
10 total
How are REXED’s laminae numbered ?
From the dorsal portion of the cord to the ventral portion
(Back to front)
Lamina 1 is also called
Lamina Marginalis
Lamina Marginalis sends what kind of signals ?
FAST/Sharp pain
via A-Delta fibers
Myelinated
Substantial Gelatinosa is comprised of what?
Combination of Laminae 2 and 3 of Rexed’s laminae
these sometimes synapse with lamina 5
Do laminae 2 & 3 synapse with other laminae?
Yes, sometimes, laminae 5
Where is substantia gelatinosa located ?
Dorsal horn of the cord, just anterior to Lamina Marginalis (lamina 1) in the grey matter
What kind of pain does Substantia Gelatinosa relay and how ?
SLOW PAIN
Via C- Fibers
Non-myelinated
Mechanoceptors synapse where in the cord ?
Anywhere through lamina 1-6 in the grey matter
What are Rexed’s Laminae 7- 9? And where are they ?
Lamina 7-9 are located in the anterior horn of the grey matter
These are where motor neurons live and can be activated by descending motor pathways
Can laminae 7-9 send action potentials?
Yes. If they are stimulated enough
What is laminae 10 (X)
Central canal of the cord where cross over can happen.
What are the DESCENDING Pathways?
DESCENDING are motor pathways
ExtraPyramidal Tracts
Corticospinal/Pyramidal Tract
What are the ASCENDING pathways called ?
ASCCENDING are afferent sensory pathways comprised of
Anterolateral/Spinothalamic tract
Spinocerebellar Tract
Dorsal-Column Medial Lemniscal System (DCML
How many different Anterolateral/Spinothalamic tracts are there ?
Two
Anterior and lateral spinothalamic tracts
1 of each on each side of the cord ! (2 types, 4 tracts)
How many types of Spinocerebellar Tracts are there ?
Two
Posterior and Anterior Spinocerebellar tracts
1 of each type on each side of the cord
2 types , 4 tracts
How many types of DCML are there ?
TWO
Fasciculus Gracilis (medial dorsal portion)
Fasciculus Cuneatus (lateral dorsal portion)
2 types, 4 total
Are Pyramidal tracts ASCENDING or DESCENDING ?
DESCENDING
Where is the internal Capsule ?
Just outside the thalamus
What signals get sent through the internal capsule? Ascending or descending ?
BOTH
sensory afferent information on its way to the parietal lobe goes through the internal capsule
AND
Descending motor signals are also sent through the internal capsule.
what structure do all signals have to pass through ?
The medulla
Where are the pyramids ?
the medulla
What is the primary pathway of the major motor tract?
Corticospinal Tract
Originates at the cortex ->
Internal Capsule ->
Pyramids of Medulla ->
(Crosses over at Pyramidal Decussation) ->
Descends down the Lateral Corticospinal tract.
Which tract takes care of the most of our motor function and how much ?
Primary Pyramidal tract
80%
What is the name of the secondary motor pathway ?
Anterior Corticospinal tract
What percentage of motor signals are the Anterior Corticospinal tracts responsible for ?
17 %
Does any motor information not cross over at all?
2-3%
Schmidt doesn’t know where
What are pyramids ?
Ridges of the medulla
Describe the pattern of the medullary decussation
Cross hatch
Are there pyramids in the Pons?
NO
Where is the primary motor pathway?
Lateral to the dorsal horns
Where is the secondary pathway ?
Anterior close to the AWC
Where does the secondary pathway cross over ?
At the level of the cord where it needs to interact with a motor neuron
Can incoming sensory information choose its own path in the spinal cord?
YES.
Enters through dorsal rootlets and chooses based on which tract is a function of the tissue
Are pain pathways ascending or descending ?
Ascending
What are the pain pathways called?
SPINOTHALAMIC / ANTEROLATERAL tract
What are the 2 main divisions of Spinothalamic tracts?
FAST pain
SLOW pain
How is FAST pain transmitted through Spinothalamic/Anterolateral Tracts?
A-Delta myelinated fibers
What are the pain sensors of the FAST Pain Spinothalamic/Anterolateral tracts?
Nociceptors - free nerve endings
Via A-Delta myelinated fibers
What neurotransmitters do the FAST pain division of the Spinothalamic tract use ?
Glutamate, always.
It’s always fast in the spinothalamic/anterolateral tract
What connects the pain sensors to the next order neuron?
Neurotransmitters !
Glutamate, always in Fast tract
Glutamate, Substance P, and Calcitonin Gene Related Peptide (CGRP)
What is the fast pain pathway?
Ascends the cord via ANTEROLATERAL tract->
through the VENTROBASAL complex just outside the THALAMUS ->
And Projected to different parts of the PARIETAL lobe
What kind of pain is best localized ?
FAST / sharp pain signals
Via the parallel system in the DCML
FAST Pain route:
Lamina 1
Cross over at AWC in the cord Anterolateral/Spinothalamic tract
(Lateral portion)
Ventrobasal complex w/ DCML sensory information
Called NEOSPINOTHALAMIC tract
What’s the other name for Slow pain tract ?
Paleospinothalamic
Ex: Dinosaurs
What is the main neurotransmitter the slow pain tract uses ?
Substance P mainly used in slow pain pathways
Where is slow pain projected to ?
Top of the brain stem & not much further
Why is slow pain poorly localized ?
No parallel system with DCML
Where does slow pain synapse in the cord ?
Laminae 2 & 3
(Sometimes 5 )
What tract does slow pain take?
Anterior portion of ANTEROLATERL tract
What part of the brain allows us to localize pain ?
Somatosensory areas
What engages our emotions?
SLOW pain
Why does slow pain mess with our head?
Closer to the middle of the brain where the brain stem connects to diencephalon
What is the Reticular Formation ?
Swath of tissue on top of the brain stem where most slow pain signals terminate
What are the ExtraPyramidal Tracts?
Vestibulospinal - balance & eye fixation
Olivospinal - just know it exist
Reticulospinal - muscle tone
Rubrospinal - voluntary movement
Are ExtraPyramidal tracts ascending or descending?
DESCENDING motor tracts
Vestibulospinal
Olivospinal
Reticulospinal
Rubrospinal
How many overall pain signaling systems do we have and are they afferent or efferent?
TWO
DCML - ASCENDING - major pressure/touch/vibration
DIC (DESCENDING inhibitory Complex) - descending pain suppression system
What does the first neuron in the DIC release?
First order RELEASES Enkephalins in the middle of the pons.
Where do DIC pain suppression signal originate?
Periventricular Nucleus or
Periaqueductal Gray
Where is the periaqueductal Gray ?
Near cerebral aqueduct and third ventricle
Where is the periventricular nuclei located?
“Right in front of the third ventricle
How many neuron orders are there to transmit pain signals?
THREE orders
What kind of neuron is the second order neuron ?
SEROTONERGIC - 5-HT
Released in the spinal cord near dorsal horn
Where is the Serotonergic neuron ?
Excited by 1st order neuron in the pons stretches down to dorsal horn and releases serotonin there.
What are the responses to released enkephalin in the brain?
Excitation of second order descending neuron
What is the response of serotonin being released in the spinal cord?
Acts on third neuron in DIC.
This neuron is an enkephalin secreting neuron
What does the third order neuron secrete ?
ENKEPHALIN
What is ENKEPHALINS function in the spinal cord?
An inhibitory neurotransmitter
Where are enkephalin receptors?
On nociceptors that reach into the periphery.
And the second neuron in the ascending pain pathway
What is ENKEPHALIN ?
Endogenous morphine analog
All of our opiate receptors are what ?
ENKEPHALINS
Where is the first synapse in the descending pain pathway ?
RMN
Raphe Magnus Nucleus
What is 5-HT ?
Serotonin
Where is the RMN ?
Raphe Magnus Nucleus - middle of the pons
-first order synapse of descending pain pathway
Enkephalin released in the dorsal horn has what response ?
Released enkephalin at the synapse in the dorsal horn can shut down the pre - and post - synaptic side of synapse . Lowers activity of both neurons (Ascending and descending portions)
What types of pain does the DIC complex target?
SLOW and FAST pain
Descending Pain Suppression System route ?
1st order - originates at periaqueductal or periventricular
{Releases Enkephalin}
Excites 2nd order in Pons
2nd order descends to cord and {releases serotonin }
Serotonin excites 3rd order neuron that reaches into grey matter of dorsal horn
{releases Enkehphalin
Ascending Pain route ?
1st order - Nociceptors from free nerve endings in periphery
Synapse with 2nd order in dorsal horn (lamina 1,2,or 3)
crosses over cord at AWC and ascends anterolateral columns
How do some people have higher pain tolerances ?
Meditation , inner - wellness, long and hard training that probably modulates the DIC
What is pain?
“A survival thing
Tells us when were doing something stupid “
-Schmidt
What does chronic pain increase ?
With chronic pain we have more neurotransmitter receptors within the pain transmission system, this causes glutamate receptors to get up-regulated and the system becomes more difficult to inhibit with enkephalin analog.
- Reductions in enkephalin receptors and increases in glutamate receptors in the pain system
What will nociceptors deem as pain ?
Damage /cuts = depolarization = PAINful
Acidosis - builds up with workouts
Potassium - dialysis pts
Histamine - swelling
5-HT - in periphery
ACh - in periphery
Bradykinins
Prostaglandins - increase sensitivity to pain !
what does increasing bioavailability of serotonin do ?
Should increase the inhibition of pain by inhibiting the re-uptake of serotonin
What order will SSRI’s effect?
Augmented effect on THIRD order inhibitory neuron
Examples of SSRI’s given by Schmidt ?
Paxil
Prozac
TCA’s - older drugs with other effects
But used for chronic pain
One side effect of TCA’s that can help chronic pain ?
Cause drowsiness
- chronic pain people have trouble sleeping, so TCA’s allow them to actually sleep due to its sides effects
Extra Serotonin does what?
Encourages increased release of Enkephalins to help suppress pain
What is the divergence of DCML pressure sensors?
DCML run parallel to pain signals, follow same route into dorsal horn, but then Ascends in dorsal columns .
What is the decision making apparatus of the cord?
grey matter
Lateral Inhibition works when two what run parallel?
A nociceptor (pain signal )
A pressure sensor (DCML)
Where does lateral inhibition occur?
Most likely in the dorsal end of the cord
What is acupuncture based on ?
LATERAL INHIBITION
- needles placed in various pressure points can deaden the pain signals running in that area
What is Glutamates natural state?
Excitatory
- main neurotransmitter for pain transmission
What causes Glutamate to release from 1st order neuron ?
Ca++ coming into 1st order neuron
-usually in reaction to some previous action potential
What is the Primary glutamate receptor in the pain system ?
AMPA-R’s
What ion are AMPA-R’s permeable to ?
Na+
Other Glutamate receptors ?
NMDA receptor
What is the primary current allowed in NDMA-R’s
Ca++ (Primary )
Some Na+
What do NMDA-R’s require to open ?
- Initial Depolarization to removal blockade of Mg+
- Glutamate binding
Allows Ca++ to come in after magnesium removal
Also adds to why NDMA-R is slower than AMPA
Which glutamate receptor is fastest?
AMPA-R
What sends pain information faster, AMPA-R or NDMA-R?
AMPA-R reacts and opens faster, this depolarization can allow NDMA-R to open and will DOUBLE the rate at which we sent the signal
Where do NDMA-R come from ?
Important part of development from birth
What blocks NDMA-R’s?
Alcohol
Lead
Ketamine - dissociative
Nitrous
tramadol
Does Ketamine work on NDMA and AMPA receptors?
No ONLY NDMA
Can pain signals still be sent with ketamine ?
YES
But perception of pain is different
Dissociated from normal
How does tramadol work ?
“Terrible drug”
Decent SSRI , and NDMA antagonist
Does nothing for narcotic or enkephalin receptors
What increases NDMA and AMPA receptors?
CHRONIC PAIN will populate more of these receptors at the synapse
Will increase action potentials or sensitivity to pain
Other type of glutamate receptor?
Kanate
What are the three ionotropic glutamate receptors?
AMPA
NDMA
Kainate
what are Metabotropic receptors?
G-protein coupled receptors involved in signal transduction of nervous system
Second broad category or glutamate receptors
Can NDMA-R’s be decreased in population ?
Over long period of time
what kind of ion channel do we have in first order pain neuron?
Voltage Gated Ca++ channel
- no class given
Will DIC take away all the pain ?
Not all the pain all the time, but gives us a good target with anesthetic drugs
What kind of receptors are enkephalin receptors ?
G-protein coupled opiate receptors (7-transmembrane)
What are opiate receptors usually linked too ?
potassium channels
Where are opiate receptors?
on both pre and post synaptic cell
what other receptors are also found on pain synapses ?
ALPHA 2 receptors
Alpha 2 receptor activation at the pain synapse causes what ?
open K+ channels
can shut down 1st and 2nd order nociceptors
Example of alpha 2 agonist drugs that stimulate pain synapse
Xylazine - not most specific
Clonidine - mid specificity
Precedex - most alpha 2 specific
Xylazine , Clonidine, and precedex will have what effect when stimulated ?
general pain suppression, slows down CNS system, less euphoric, less addiction concerns
Which alpha 2 agonist is usually abused ?
xylazine - horse tranquilizer
General effects produced by volatile anesthetics?
suppress CNS activity
can loose consciousness and decrease ability to feel
How do volatile anesthetics work
cause general increase in Potassium conductance at the synapse
MOA of volatile anesthetics?
open K+ channels and increase potassium conductance
Potassium is always doing what?
LEAVING the cell!!
How does COX-2 affect pain ?
produces prostaglandins that interact with 1st&2nd order neurons, increases SENSITIVITY to pain !
COX-2 can be expressed where in the pain pathways ?
1st and 2nd order ascending pain neurons
How do PGs work in pain ?
increase likelyhood of an action potential by increasing the expression of receptors on 2nd order neuron
How does Nitric Oxide work in pain pathways ?
increases sensitivity to painful stimuli.
Mg+ does what in the synapse of pain
blocks NDMA receptor activity.
OTC Magneisum is safe but causes GI upset
Do extracellular Ca levels affect pain ?
NO
does Ca suppress pain ?
No, ,decreases neural activity but doesn’t help with chronic pain
COX-2 is induced by what ?
can be induced by pain
iNOS
Inducible Nitric Oxide Synthase
What are the four reflex pathways ?
Stretch
Tendon
Withdrawal
Crossed Extensor
Which reflex pathways are stretch or tension ?
Stretch and tendon reflexes
which reflex pathways are pain ?
Withdrawal and Crossed Extensor
Basic wiring for all reflexes ?
Sensory Neuron
Alpha motor
Interneuron
What sensory things can cause a reflex ?
pain, tension , stretch
afferent portion
Where are reflex sensors located in the body?
sensor in periphery and springs embedded in the muscles that sense tension or pain
How do sensory and motor components of muscles talk to each other?
direct connections or interneurons (1 or many)
where do motor neurons hang out ?
ventral/anterior horn ( front.)
efferent portion
what are interneurons ?
intermediary neurons - bridge between sensor and motor neuron
and between two sides of the cord
can be excitatory or inhibitory
Is there a direct path from the dorsal horn to opposite side of cord ?
NO . need interneuron
Which reflex is weight bearing, helps us maintain posture, and does not need interneurons ?
STRETCH reflex
does not need interneurons has direct synapse on motor neurons but can use them sometimes.
What is the stretch reflex useful for ?
standing up
keep posture constant
keep muscles at a constant length
What receptors does the stretch reflex use ?
muscle spindles - springs
How would you clinically test to confirm intact stretch reflexes?
stretch reflex with tendon hammer
What happens with a stretch reflex test ?
patient position with leg dangling
hammer is tapped at patellar
the stretching induced by hammer tap stimulates stretch sensory receptor (Muscle spindle)
then exciting the sensory neuron
Sensory neuron activates motor neuron in the spinal cord.
excited motor neuron then activates effector muscle - which contracts and relieves the initial stretching.
Which Reflex prevents muscle from being pulled out of the bone?
TENDON
embedded in the collagen of our tendons
which reflex is the simplest ?
STRETCH
weight baring reflex
Imbalance from the head would cause a stretch in which muscles?
Quads
Stretch causes what ?
reflex activation of muscles being stretched
stretched muscle will contract then release
What do inhibitory interneurons of the stretch reflex allow ?
reflex relaxation of the antagonistic muscle
relaxing would help straighten out the muscle
Where are the sensors for the Tendon reflex?
Golgi Tendon sensors embedded in tendons of skeletal muscles
Can Tendon reflexes be turned off ?
Yes, can be deactivated to lift a car off a kid, but not known how.
How many interneurons do tendon reflexes connect with?
TWO
one excitatory
one inhibitory
what is the job of the inhibitory interneuron in the tendon reflex pathway ?
inhibitory is in charge of inhibiting activity in the motor neuron attached to effector muscle group = RELAXES
what is the job of the excitatory interneuron in the tendon reflex pathway ?
excitatory causes reflex activation of the antagonistic muscles = CONTRACTION
How does reflex activation of the tendon reflex serve ?
to pull muscle away from the intense tension its sensing.
tendon reflex involves which side of the body ?
usually unilateral ( one side )
Stretch reflex involves which sides of the body ?
unilateral
Flexor Reflex is known as ?
WITHDRAWAL Reflex
Withdrawal / Flexor Reflex is stimulated by what ?
pain
Withdrawal / Flexor Reflex involves which muscles ?
FLEXORS - to pull away from pain
Which side of the body does flexor reflex involve ?
unilateral on its own
no interneurons crossing over
Can Flexor reflex engage antagonistic muscles ?
yes, will cause relaxation to help speed up withdrawal from painful stimuli
What happens with flexor/withdrawal refelx when we encounter pain ?
activation of flexor muscle = flex of muscle to pull away
Does flexor/withdrawal reflex only involve one level of the spinal cord ?
NO. usually unilateral
but engages a couple spinal vertebrae levels up and a couple down (2 up/2 down)
How does flexor/withdrawal reflexes recruit other levels of the spinal cord ?
interneurons that ascend and descend the cord
CELL BODY IN WHITE MATTER
Where does the ascending and descending interneuron live ?
tract of Lissaur
Where is the tract of Lissaur
dorsal border of the dorsal horn
CELL BODY IN WHITE MATTER
What is the flexor/withdrawal reflex useful for ?
pain and pressure to detect potentially life-threatening stimuli , usually when body is not in motion
Most complicated reflex ? and why ?
Crossed Reflex/ Crossed Extensor Reflex
involves both sides of the cord
more useful with bodies in motion
why does the crossed extensor reflex involve both sides of the cord ?
helps us maintain out balance/ support our bodies as we pull away from source of pain
How many levels of the cord does the crossed Extensor involve?
multiple levels and both sides of the cord
What happens in effector muscle group with crossed Extensor Reflex?
contraction of flexors in effector muscle and antagonistic relaxation of extensor muscles in effector leg
What happens in the muscle groups of non stimulated muscles with crossed extensor reflex?
activation of extensor in non-effected leg , and relaxation of flexor group of this leg
Which reflex uses most interneurons?
Crossed Extensor Reflex
ALL reflexes are
Protective in nature
What receptors are at the NMJ ?
MATURE nACh-R
Where should we find mature nACh-Recptors?
AT THE NMJ should not be anywhere else
How many subunits make up the nACh-R ?
5 subunits
2 Alpha binding sites
1 Epsilon - in between alphas
1 Delta
1 Gamma
Mature nACh- R have what kind of flow ?
HIGH conductance channels
high current , high permeability , high speed of ions moving through
What are Immature nACh-R?
Fetal nACH-R
populated by our CNS when our body detects something wrong or no feedback form muscles
usually in strokes
Describe the domain of a immature nACh-R
2 alpha sites, 2 GAMMA , 1 delta
Placement of fetal nACH-R ?
Can be expressed on other parts of the muscle - outside the NMJ
Fetal nACH-R conductance ?
SLOW , less current , LOW conductance - but open longer
Concern with low conductance fetal nACH-R?
extended response to NTs = longer reaction - especially to succ’s
what is the third type of nACh-R?
alpha 7 -in CNS
7 alpha binding sites
What sends information back to the brain to confirm or deny muscle contraction ?
muscle spindles
What kind of nACH-R does the CNS populate ?
only fetal nACh-Rs. not mature ones. they mature throughout our development
What else do fetal nACh-R ‘s allow for ions ?
a place for K+ to hemorrhage through
Can cause VFib
Post junctional area
furthest from NMJ
nACh-r should NOT be here
should not be effected by activity in NMJ
Peri-Junctional Areas
In between post and junctional area
may be effected by junctional area activity
Junctional area
where motor neuron talks to skeletal muscle
where nACh-r should be , where ACh binds to receptors to send action potentials etc
Supramaximal Stimuli
a stimulus trong enough to recruit all muscles in contraction
what clinical testing do we use to test nervous systems talking to motor neurons?
Neuromuscular Monitoring
Neuromuscular responses mean what ?
large contraction - minimal block if any
small contraction - block is transitioning out or deeper
no contraction - very deep block
Train of Four
repetative stimulation at 2hz over 2 secs each (4 twitches
How do electrode work with neuromuscular stimulants ?
takes away the natural polarity difference from the inside and outside
removing this with electrode stimulants is DEPOLARIZING
Train of four ratio ?
B/A
b= fourth twitch (if any )
a= first twitch
as drug approaches 1 drug is wearing off
non-depolarizing twitch assessment
staggered - as drug wears off TOF increases
depolarizing twitch assessment
even - first and last contraction are similar
incomplete block with depolarizing twitch assessment
height will all be the same
tetanic
muscle contraction that occurs when a muscle is stimulated at high speed and frequency
post -tetanic count
counting the number of impulses a muscle generates after a tetanic contraction
Double burst stimulation
multiple tetanic contractions in a series
two short burst of three pulses each at 50 hz (high frequency)
where do we apply electrodes for neuromuscular monitoring ?
Adductor Pollicis - thumb & pinky
opthalamic branch - eye brow
perineal nerve - butt
posterior tibial nerve - lower leg extension
Non-depolarizing onset and offset ?
few minutes onset , offset hours
depolarizing onset and offset?
fast onset - offset three minutes
SUCC’s is cheap and fast
why is succs popular ?
fast onset, fast offset, cheap, and can be given IM
how many twitches do you need to determine a TOF ratio?
FOUR
non-depolarizing blocks effect what part of the synapse?
inhibit both sides of synapse
depolarizing agents effect what part of the synapse ?
more effect on skeletal muscles (but also both with different effects)
What are autoreceptors ?
Alpha-3 , Beta-2 - second type of ACh recepotors on motor neuron
where are autoreceptors found ?
motor neuron
What do autoreceptors do ?
bind to dumped ACh from same neuron, allows Na+ influx (some Ca+) , causes long term NT stores (VP-1) to merge into VP-2 form
What breaks down Succinylcholine ?
Plasma cholinesterase - function out of the liver
are L-type Calcium Channels required for normal motor function ?
NO.
P-Type is required
will CCB paralyze a patient through P-type or L-type Ca+ Channels ?
P- Type channels.
L-type are not required for normal motor function
P-Type Ca+ Channels have what effect on CNS ?
depression of CNS
Phrenic nerve originates where ?
C-3, 4, and 5
Phrenic nerve connects what ?
DIAPHRAGM to C-3,4,&5
know what forever ?
PHRENIC NERVE CONNECTIONS
C-3,4,& 5 to diaphragm
Adductor Pollicis inhibition starts at what dosages?
20mcg/ kg
40mcg/kg is total inhibition
Total inhibition of Adductor Pollicis is seen at what dosages?
40mcg/kg
What order do muscles recover after paralysis ?
in order of importance
DIaphragm will recover first.
Diaphragm inhibition starts at what dosages?
40 mcg/kg
total inhibition 90-100
Total inhibition of Diaphragm is seen at what dosages?
90-100 mcg/kg
What controls the diaphragm ?
PHRENIC NERVE
(C-3,4,&5)
What kind of muscle is the diaphragm ?
SKELETAL muscle
which muscles are harder to block ?
more important muscles, they have lots of receptors , requires more medication at these muscles to block
How high can a neck injury occur and maintain oxygenation ?
C-5 - you can breathe
C-4 - depends
C-3 - you will suffocate
How many twitches will you see with 70-80% blockade?
3
fourth twitch should disappear at this percentage of blockade
How many twitches will you see with 85% blockade?
2
third twitch disappears at this blockade
How many twitches will you see with 85-90% blockade?
1
second twitch disappears with this blockade
How many twitches will you see with 90-95% blockade?
0
all twitches should disappear at this blockade
Neuromuscular monitor settings?
50-80 mA
Is a NM blockade a supramaximal stimuli ?
YES
how many skeletal muscle cells does a motor neuron control ?
ONE
exception - ocular muscles
How can succinylcholine increase IOP?
causes leakage of Ca+ at NMJ which can cause the eye socket to contract just enough to increase IOP
chances increased with head down
What would a reduction in GABA neurotransmitters cause ?
uncontrolled overactivity of the CNS (seizures )
What do GABA neurotransmitters cause ?
increased chloride permeability
Where does K+ leave from with succs ?
- primarily through leak channels
- VG K+ channels
- loss through ACh-R’s
Which Neurotransmitters are inhibitory ?
GABA and GLYCINE
what is the MOA of Glycine ?
unknown
but inhibitory in nature and very important in the spinal cord
Which Neurotransmitters are most inhibitory in the spinal cord ?
GABA and GLYCINE
ACh, MOA and effects ?
allows nervous system to talk skeletal muscles
increases alertness/awareness
how do anticholinergics cause drowsiness ?
they block ACh which usually increases alertness/awareness
What does GABA do in the brain ?
limits neuronal activity
Treatment for Alzheimers ?
Centrally acting ACh-ase inhibitors (-stigmine)
-can cross BBB and enhance ACh activity at m-ACh-R
where does ACh awareness come from ?
MUSCARINC ACh-R
what OTC drug is good at blocking mACh-R’s?
BENADRYL
cross reactivity with histamine
large dose can increase HR
inhibition of ACh-ase causes what?
increases awareness / activity
Side effects of ACh-ases ?
waking patient up too early
decrease HR - through reduce mACh-R at heart
increased gland secretions/ mucus
Histamine has what effect ?
increases awareness
reduce histamine will make you drowsy
Glutamate facts
stimulatory in nature
increases neuronal activity - can burn out CNS
Dopamine is associated with what ?
pleasure and reward
and motor inhibitor
more we reward- more released
what neurotransmitter are Parkinsons patients missing ?
DOPAMINE
shakey from lack of dopamine which naturally inhibits motor
Norepinephrine has what effects ?
increases awareness
which NT’s increase awareness ?
ACh
Histamine
Glutamate
Norepinephrine
GABA , GLYCINE, and DOPAMINE all have what similar effect ?
prevent CNS overactivity
ACIDOSIS causes what centrally ?
CNS activity is reduced
ALKOLOSIS causes what centrally ?
CNS activity is increased
what are acid- base imbalances related to ?
Ca levels
Causes of acid - base imbalances ?
Direct increase or decrease in protons
and CO2 levels
how does the body manage acid-base imbalances ?
chemical reactions
ACIDOSIS reduces CNS activity how ?
causes more protons to bind to Albumin - which means less Ca+ is bound to albumin and increased in the ECF = reduced CNS activity
ALKALOSIS increases CNS activity how ?
causes less protons to be bound to albumin, so Ca would bind to it- decreasing the free Ca+ and increasing CNS activity
With hypoventilation what would increase?
increase in protons - which would bind to albumin- leaving increased free Ca - reducing/inhibiting CNS activity
Which circulations are good at autoregulation ?
Cerebral and spinal (within reasonable blood pressure range)
How many spinal arteries do we have ?
3
1 in the front in the anterior median fissure
and 2 posterior on each lateral side
Whats the different in the blood supply of the three different spinal arteries ?
anterior artery - 75%
posterior arteries collectively = 25%
whats the source for the spinal arteries ?
posterior - combination of vertebral arteries (neck) , and cerebellar artery (anterior inferior and posterior inferior Cerebellar arteries.)
Lower in the cord source of blood is from intercostal arteries that branch into the radicular arteries then feed into main spinal area
What are radicular arteries ?
Branches of intercostal arteries
can feed into front or bakc of cord
Intercostal arteries are combined of what ?
form to make radicular artery and feeds into the front OR back of spinal artery.
NOT front and back on the same level of the cord
Are feed vessel patterns the same for everyone ?
feed vessel is irregular
explain feed vessel pattern for the spinal arteries
every 5/6 levels artery will come in from either side of the body and feed anterior OR posterior spinal cord
What else are radicular arteries called ?
segmental
medullary
or both
segmental medullary arteries
where are coronal arteries found ?
outer surfaces of the cord
coronal means crown - they do not wrap all the way around the spinal cord
whats one big difference between Cerebral circulation and spinal circulation ?
spinal cord doesn’t have circle of willis which means circulation cannot continue with collateral circulation.
what vessel do we have at every level of spinal cord ?
Spinal branch
Does the Aorta connect to the spinal cord on every level ?
NO
What is the posterior radicular artery ?
a feed vessel that branches from the posterior spinal artery into the dorsal portion of the cord
What are some arteries attached to the aorta ?
Intercostal arteries, thoracic arteries, renal arteries, mesenteric arteries
what is the anterior radicular artery ?
feed vessel that branches from anterior spinal artery
Is cross clamping above the GRA okay for aneurysm repair?
NO, above the GRA increases risk and concern for paralysis of lower extremities
Where is it okay to cross clamp on the GRA ?
Below, this may cause sensory loss, but lower risk of paralysis
What can cross clamping cause and how ?
cross clamping of the aorta or GRA can cause neuron death due to decreased perfusion and can lead to paralysis
What can help in decreasing risk of paralysis due to decreased perfusion from cross clamping ?
imaging to locate where GRA and aorta are
anything that reduces inflammation in the cord
and drugs can be given to slow metabolic rate
Clamping below the GRA also increases possibility of what ?
less ischemia to lower extremities
and normal blood pressure
What determines how dangerous aneurysm repairs are ?
the branch point
normal CSF pressure ?
10 mmhg
How much can cross clamping increase CSF ?
10 mmHg
normal ICP
10mmHg
perfusion pressure for cerebrum equation ?
MAP - ICP
How can un-clamping artery be bad ?
rapid re-perfusion can cause damage from rapid influx of oxygen to vessels that have been deprived for a period of time.
What worse, loosing perfusion in a posterior or anterior spinal artery ?
Anterior spinal artery - we only have one
how many feed vessels go into the neck from the anterior spinal artery?
two feed arteries.
How many feed vessels are in the throax from the anterior spinal artery?
2-3
how many feed vessels are in the lumbar portion from the anterior spinal artery ?
1-2
What feed vessel takes care of 2/3rd arterial blood supply to lower extremities
GRA Great Radicular Artery
Whats another name for the GRA ?
Adamkiewicz
who is Adamkiewicz?
the GRA
Where does the GRA come from in most patients ?
LEFT - closest to the aorta
What spinal level is most associated with the GRA (Adamkiwicz) ?
T10 - “pick this”
T9-T12 = 75% - vast majority
absolute ranges T5-L5
Adamkiwica branches off of what ?
the aorta !!!!
Low MAP makes it hard to perfuse what ?
EVERYTHING
What can help lower CSF pressure?
drain
What are the Spinocerebellar tracts ?
ascending feedback tracts
Anterior and Dorsal spinocerebellar
which ascending spinal tract delivers information about activity in the anterior horn ?
Anterior spinocerebellar
sends information back to anterior lobe of cerebellum through the Superior Cerebellar Peduncle
which ascending spinal tract delivers information about tendons and muscle spindles ?
Dorsal Spinocerebellar
sends information back to posterior cerebellum through Inferior Cerebellar Peduncle
What are the spinocerebellar tracts help with ?
sensors in periphery collect and send this information to help the cerebllum coordination of complicated movements
How much of our total body mass is skeletal muscle?
40%
What is skeletal muscle used for ?
communicate, regulate body temperature, defending ourselves, energy storage
where is glycogen stored?
skelettal muscles and liver
Ligaments connect what?
bone to bone
patellar/ACL/MCL
Tendons connect what ?
MOSTLY muscle to bone
What is a intermediary tendon ?
muscle to muscle connection
“tendon bridge”
Muscle Fibers are what ?
individual muscle cells
Fasciculous
grouping of multiple skeletal muscle cells seperated by connective tissue - functions as a unit
Muscle definition
group of many Fasciculi
Sarcomere definition
basic functional unit of skeletal muscle
Myofibrils
internal cylinders within muscle cells with contractile proteins (actin and myosin)
how many myofibrils are there per skeletal muscle cell ?
200 myofibrils per muscle cell
large muscle cells have more
the stronger the muscle the more myofibrils ?
YES /TRUE
are weaker muscle cells okay ?
yes having SOME weak muscle cells give up precise control
myofibril contractile unit is called what?
Sarcomere
Thick filament
MYOSIN
thin FIlament
ACTIN
what happens at the overlap of actin and myosin?
ability to produce force
What is a motor unit ?
collection of one or more skeletal muscle cells/fibers controlled by a single motor neuron
fewer skeletal muscle cells
make up small motor neurons
these are delicate and dont contract super fast
small motor neurons are used for ?
fine motor tasks and control
easy to exicte but do not contract fast
Are Large Motor Neurons easy to excite ?
NO , they require larger stimuli
whats the order of activation for motor neurons ?
small motor neurons activate first then larger motor neurons become activated
Can we selectively recruit large motor neurons?
no, not with out recruiting smaller ones as well
Type 1 Classification of muscles
red in color - dark meat
slow contractions that can be sustained
lots of mitochondria - run through ATP
lots of myoglobin iron containing protein to help O2 unload from blood into the muscles
Type 2 Classification of Skeletal Muscle
white muscle - fast twitch
produce strong force but unsustained
less mitochondria, less myoglobin
What is organ pain
Visceral and Parietal
What is Visceral Pain ?
Internal organ pain poorly localized and transmitted via CNS
What os Parietal pain ?
tissue pain localized fairly close to where the pain is
What kind of pain is Parietal Pain?
FAST pain via A delta fibers
What kind of pain fibers would Visceral pain use ?
slow C-fibers
What is pain threshold?
ease or difficulty of eliciting a painful feeling
high degree of variabilty
What organs do not have pain sensors?
Soft tissue in the lungs
and the liver itself
Where does kidney pain get referred to ?
lower back
what is decompression pain ?
pressure place on pain of lower right quadrant - usually helps pain until pressure is removed
Can visceral pain be relieved with pressure?
no - due to lack of lateral inhibition
Where does heart pain radiate and why ?
Left shoulder or arm
R heart is less prone to ischemia - lower pressures on right side
Soleus Muscle
calf muscle - weight bearing , sustained force
Ocular muscle contractions
fast and short contractions - less myoglobin, and mitochondria
Gastrocnemius is where
next to soleus muscles
- sustains contraction longer than ocular but not as long as soleus , due to weight
Sarcolemna
cell wall of skeletal muscle
Sarcoplasm
fluid inside skeletal muscleS
SR
Sarcoplasmic reticulum specialized endoplasmic reticulum for muscles
Myosin Filament tail contain what ?
two long strings of myosin molecules wrapped together at the tail
Myosin head contains what ?
1 set of Essential Lite Chains (2)
1 set of Regulatory Lite Chains (2)
Myosin filaments are made of how many chains total
6 chains total , 2 tails wrapped and 2 sets of head
What determines the shape change of Myosin heads in smooth muscle ?
Regualtory lite changes determine shape change after phosphorylation
F-actin is responsible for ?
binding sites for myosin head
Tropomyosin functions as what ?
a shield - hides active sites on actin from myosin - musy be moved to induce contraction
What is the troponin complex comprised of ?
Troponin I
Troponin T
Troponin C
Troponin I binds to what ?
Binds to actin strand
Troponin C binds to what ?
binds to Calcium
-4 binding sites for Ca++
Troponin C binds to what ?
Ca++
Troponin complex is used for what ?
causes configuration changes on actin to loosen and expose binding sites.
“Cocked” State of myosin head in cross bridge cycle
heavy chain tail of Myosin is perpindicular to Actin and attached to Phosphate and ADP in its ready to bind state.
Weak cross bridge state of cross bridge cycle
Ca binds to troponin C or troponin complex, causes conformational change and exposes the binding sites of on actin
Strong (power stroke) cross bridge state
Myosin head binds to troponin I and the head bends pulling the actin over the myosin with strong force toward the center of the sarcomere. Phosphate is released.
Post Power stroke stage of cross bridge cycle
ADP remains on myosin head which sustains contraction
Attached state
ADP falls off eventually but head remains in place until another ATP comes to detach the head
Released State of Cross Bridge cycle
ATP releases tension of myosin head and is metabolized into ADP. then the cycle repeats.
Problems with cross bridge cycle
run out of ATP = no force = stiff muscles
Sequestrin Protein
Stores Ca to remove from SR
What connect bone to bone?
LIGAMENTS
What connects muscle to bone?
TENDON
Over lap of thin and thick filaments is called what ?
A BAND
How many classifications of skeletal muscle are there ?
two - Type1 and Type 2
How many skeletal muscle motor units can a motor neuron control ?
1 OR MANY
What are the 5 layers that make up the cell ?
Sarcomere - Stretch
Myofibril
Muscle Fiber Cell -NMJ
Fasciculous
Muscle (Fasiculi)
What part of the muscle is the NMJ ?
Muscle fiber cell
What layer of the muscle is responsible for the stretch ?
Sacrcomere
Is there a axon terminal on every single muscle fiber cell?
YES
without it the muscle would be useless
This is found at each end of each sarcomere
Z-Disc
Whats wrapped around the Z-Disc
Actin is wrapped around ends
Place where we have only thin filaments
I BAND - actin only - light in color
Darker colored area where there is only thick filaments
H ZONE/BAND
this connective tissue holds our thick and thin filaments together
titin
How many myosin molecules make up each myosin filament ?
200
Contracted Sarcomere
z - disc are pulled closer together
I band shrinks
A stays the same
Is the force of contraction directly related on stretch of heart muscle ?
YES . Frank Starling law.
Heart is usually slightly under-stretched at rest
Passive tension is what ?
Outside tension/force to stretch muscle from tendon
Active tension is what?
force produced in the skeletal muscle as a result of the AP
Passive tension + Active tension is what ?
TOTAL Tension
stretch happens where that increases performance ?
stretch at the tendons - lengthens muscle tissue
