A&P Test 3 Flashcards
what is the space on the skeletal muscle called where the neuron comes in close contact with the skeletal muscle, Where ACh should be concentrated
junctional
if we look outside of the junctional area, what is this area called?
peri junctional
What is the area called that is placed past the peri junctional area?
post junctional
What areas regarding an normal nACh synapses should be affected with succs?
junctional
maybe peri junctional
in a normal synapse with ACh, which area should be able to repolarize easily after being given succs?
the post junctional area
how can we keep tabs on how well our paralytics are working?
neuromuscular monitoring
place electrodes on a nerve and run current through them. This should generate an action potential and cause contraction of nearby muscles
what is the physiology of using an electrical current to stimulate a contraction?
the inside of the cell is negative and outside is positive in a normal resting neuron.
We have one cathode and one anode. We send electrons (negative charge) on the outside of the cell from one electrode to the other thereby making the outside of the cell more negative.
When the outside and inside of the cell are both negative, there is no polarity between them and so that depolarizes it.
fast sodium channels are triggered
no polarity from the outside of the cell and inside of the cell means that it is
depolarized
when we start looking at EKGs, we will start looking at the current that runs
outside of the heart
What is the voltage called that creates a strong enough depolarization that it should not have a hard time generating action potentials in all the underlying neurons?
supramaximal stimuli
why do we use supramaximal stimuli?
Because it gives us a good baseline
what are some of the settings that can be dialed into the electrodes to produce a muscle contraction?
single twitch
TOF
Tetanic
*post-tetanic count (PTC)
Double -burst stimulation (DBS)
What is the frequency that TOF uses?
2Hz/2S
2 impulses over 1 second for a total of 4 impulses over 2 seconds
Which type of block creates a pattern of the first twitch being stronger than the following twitches?
an incomplete non-depolarizing block
Which type of block creates a pattern of the all of the twitches being equal but not at baseline?
incomplete depolarizing block
what is a post-tetanic count?
a measure of the health of the synapse after a tetanic impulse.
is it ready to go after it’s fired 100 AP?
what is a double burst stimulation?
when you use tetany in short succession
what muscle group does the ulnar nerve innervate?
the adductor pollicis
what happens when you stimulate the adductor pollicis?
the thumb will move towards the palm
and/or
the pinkie will move toward the palm
What are the electrodes that are placed on the side of the palm and pinkie?
sensory electrodes that measure and graph the reaction of the muscle
what are other places than the adductor pollicis that you can monitor your neuromuscular blockade?
ophthalmic branch of the facial nerve (orbicularis oculi)
peroneal nerve (butt area)
posterior tibial nerve
in a NDMR, onset takes a few minutes to kick in, and then depending on which drug you use, you have different
half lives
minutes to hours
what does NDMR stand for?
non depolarizing muscle relaxant
why is succs very popular?
it’s cheap
-quick onset
-short half life
Succs can be given through which routes?
IM
IV
NDMR’s have a ____ half life
long
What should a base line TOF graph look like?
all of the twitches should be even
the twitches come back in ______ with a NDMR
stages
If we quantify the strength of the twitches of the first and last twitches on a NDMR, we should be able to express this as a ratio. what is this called?
the TOF ratio
what part of the TOF ratio relates to the last twitch?
the numerator
what part of the TOF ratio relates to the first twitch?
the denominator
when the NDMR is first wearing off, you would expect the TOF ratio to be
very small
The TOF ratio tends to _____ when we get closer to baseline
increase
all 4 twitches recover ______ in a depolarizing block
evenly
non-depolarizing and depolarizing drugs work on what two places?
the skeletal muscles and the neuron
What type of ACh receptor is found on the neuron that releases Ach?
an autoreptor called alpha3beta2. It has 3 alpha subunits and 2beta subunits
how many ACh are required to open an ACh autoreceptor?
2, although there is a third spot for ACh to bind it doesn’t require the 3rd to open
where does the ACh come from that activates the autoreceptor?
from the synapse from that neuron
what comes in through an autoreceptor on a neuron? What does it do?
Na+ and Ca++
causes the VP1’s to move down towards the cell wall to replace VP2
A NDMR works on both the _____ and ______
skeletal muscle- blocks EPP
neuron- blocks auto receptor
if we block the auto receptor, we don’t have ________ which makes the subsequent action potential
VP1 converting to VP2
weaker d/t less neurotransmitter being available at the synapse
depolarizing drugs effect the auto receptor by
holding it open and continuously stimulating VP1 to convert to VP2
what breaks down succs? (a&P)
plasma cholinesterases that come from the liver
what is not required, but helps the P-type calcium channels on the neuron?
L-type calcium channels.
fairly fast to open
why can’t we paralyze someone with a high dose L-type calcium channel blocker?
because they’re not required for normal motor function
if you’re hungover and shaky, what kind of drug would help calm you down?
L-type calcium channel blocker
what are the extra fetal nACh receptors called that are added in motor deficiencies?
post-junctional nACh receptors
less important muscles are ____ effected by paralyzing agents?
More. sensitive
What is one of the last muscles to be paralyzed?
diaphragm
the diaphragm is what type of muscle?
skeletal muscle. only skeletal muscle.
important muscles are very ________ and has a higher receptor and neurotransmitter density
robust
where does the nerve originate that control the diaphragm? what is it called?
C3 C4 C5
Phrenic nerve
what is the benefit to having the phrenic nerve originate high in the neck?
it protects the diaphragm from being effected by spinal damage until C5
what is the first muscle to recover from paralytics?
diaphragm muscle
If you have a twitch in the adductor pollicis, you can assume that which muscle is no longer paralyzed?
diaphragm
4th twitch disappears when what percent of nACh-R blocked? Probably associated with non depolarizing drugs.
75-80 %
3rd twitch disappears when what percent of nACh-R blocked? Probably associated with non depolarizing drugs.
85%
2nd twitch disappears when what percent of nACh-R blocked? Probably associated with non depolarizing drugs.
85-90 %
All twitches disappear when what percent of nACh-R blocked? Probably associated with non depolarizing drugs.
90-95 %
If your patient can lift their head, you can assume that what percent of nACh-R are blocked?
70% or less
How many mili Amps could you set your stimulator to and expect a supramaximal stimuli? assuming you have a fairly high voltage
50-80mA
What is voltage in a stimulator?
the force that pushes electrons through the tissue.
what is current in a stimulator?
the amount of electrons that move through the tissue
what does potassium leave through when succs is bound?
mostly potassium leak channels
some vg potassium channels
a little bit of Calcium leaks in when Succs is bound to nAChr. if we have a bunch of fetal receptors placed throughout the muscles, we would expect more calcium to come into the cell and therefore the muscle to
contract, which is what you’re trying to prevent
the muscles in the eyes are controlled by several motor neurons , which means we have several NMJ. If we hit this muscle with succs and it holds those receptors open, we would be worried about what side effects?
Increase IOP
what is the one muscle in the body that does not cooperate and relax when you give succs?
intraoccular muscles
what does GABA do in the CNS?
increases Cl- conductance, thereby decreasing CNS activity
What does Glycine do in the CNS?
It’s inhibitory especially in the spinal cord, acts like GABA
What are the 2 most important inhibitory neurotransmitters in the spinal cord?
GABA
Glycine
Ach does what in the CNS?
increases awareness via muscarinic ACh receptors
What is an OTC mAChr blocker?
Benadryl
central histamine receptors are very similar to what receptors?
central mAChr
if you have an old antihistamine drug that isn’t very specific, they also tend to bind to
mAChr
Why would you see a spike in HR with Benadryl?
it blocks the mAChr in the heart
Benadryl is what class of drug?
antihistamine with anticholinergic effects too
If you could increase ACh at a central synapse you would probably see what effect in the patient
increase their awareness
What would increase the amount of ACh in the synapse?
inhibition of AChE
If you want to reverse a paralytic with a AChE but you don’t want to wake them up, what would you use?
An AChE inhibitor that does NOT cross the blood brain barrier
what is one of the treatments for Alzheimer’s disease to help “wake them up”
an AChE inhibitor that crosses the BBB
Stigmine drugs
what are some side effects of AChE inhibitors?
waking someone up that you don’t want awake
augmented ACh activity at any ACh receptor
Decrease in HR
Increase in secretions from glands (i.e. saliva/mucous)
what do histamines do in the CNS?
increase awareness, similar to ACh
what is characteristic of Glutamate in the CNS?
stimulatory neurotransmitter that increases neuronal activity when it is increased in the CNS.
meth: good awareness
What happens if you have too much glutamate?
they will burn out the brain cells and those cells won’t be replaced.
damaging to the CNS
Dopamine is associated with what area of the brain?
pleasure/reward
dopamine is a potent motor ___________
inhibitor
Parkinson’s patient have abnormally low _____ Levels which leads to _______
dopamine
hyperactive motor system
norepinephrine increases _______
awareness
Many of the older antidepressants that are used in chronic pain increase what neurotransmitter. why are they helpful?
norepinephrine, Norepi reuptake inhibitor
it increases awareness
Which neurotransmitters increase awareness in the CNS?
Ach
histamines
glutamate
norepinephrine
Which neurotransmitters work in the background in the CNS to prevent overactivity in the CNS?
GABA
Glycine
Dopamine
How does acidosis (low pH) effect CNS activity?
it is reduced
How does alkalosis (high pH) effect CNS activity?
it is increased
what buffers acids in the blood?
bicarb HCO3-
when bicarb combines with acid, we produce
carbonic acid H2CO3
carbonic acid can disassociate into
co2 and h20
what is the most significant plasma protein?
albumin
Is albumin charged?
Yes, very negative
How does albumin buffer positively charged things?
it is very negative so it attracts positives like calcium and protons
the amount of free Ca++ is dependent on what?
how many protons we have hanging around. if there are a lot of protons, they hog the albumin so that Ca++ can’t bind, leaving a lot of Ca++ free in the blood.
Increased free Ca++ _____ CNS activity
reduces
if we have a lot of protons in the ECF we would call that
acidosis
if we have alkalosis, we would expect to have ______ free Ca++
decreased
the more Ca++ we have bound to albumin leads to an ________ in CNS activity
Increase
If someone hyperventilates, a bunch of CO2 will be blown off, resulting in alkalosis. This allows Ca++ to bind to Albumin which leads to
increase in CNS activity which can lead to seizures
if someone hypoventilates, you would expect the patient to become more acidodic which would boot Ca++ off the albumin and result in a _______ in CNS activity
decrease
