Test 3 - 10/4 Lecture Flashcards
When we are born we have what nACh-R?
fetal/immature
5 subunits of the high conductance nicotinic ACh receptors
Alpha, Alpha-1, Beta-1, Delta, Epsilon
5 subunits of the low conductance nicotinic ACh receptors
Alpha, Alpha-1, Beta-1, Delta, Gamma
Normally ACh receptors should only be found in what zone?
Junctional zone
The part of the post-synaptic neuron surrounding the neuromuscular junction
junctional area
The area just outside of the junctional area on the post-synaptic neuron is called
perijunctional area
The area of the postsynaptic neuron that is furthest from the neuromuscular junction is referred to as
Postjunctional area
When giving a depolarizing agent like succs what area will it affect?
Should be localized to the junctional zone
with paralytics you’re preventing the _____ to be able to talk to the _____
Neuron
muscle
In a denervating injury we would see more immature nicotinic ACh receptors placed at what portion of the post-synaptic membrane.
Postjunctional area
In a healthy muscle we shouldn’t have any nicotinic ACh receptors in the ______
Postjunctional area
Motor neurons are found in _____
nerves
What happens when we place electrodes on top of a nerve and run current through?
Will generate and AP and cause depolarization in the nerve
If we run current through ulnar nerve and we get no twitch that would tell us what?
the block is deep
Electrical current requires one _______ and one _______
cathode and anode
Between the cathode and anode we are circulating
electrons/negative charges
If both the outside of the cell and the inside of the cell are negative then we create _________ resulting in an ________
depolarization; action potential
How do the fast Na channels open when we run electrical current on a nerve?
The current causes depolarization..this will cause the fast Na channels to open (Action Potential)
EKG’s are focused with the current on the _____ of the cell
outside
supramaximal stimulus
Strong enough to recruit all the motor neurons in the underlying nerve. Should give us a nice bit twitch.
Single twitch will show us ______ while TOF would show us _____
one impulse
More than one impulse
TOF response to an incomplete block for non-depolarizing vs a depolarizing
Non depolarizing: not all twitches at same magnitude (B/A ratio)
depolarizing: should be at an equal height for each of the twitches
Train of 4 is a stimulation that occurs
2 Hz/2 Seconds (4 impulses over a timeframe of 2 seconds)
Train of four ratio
Measured when utilizing non-depolarizing muscle relaxants B/A 4th twitch/1st twitch
Post tetanic count
Measurement of response after a high frequency (tetanic contraction) stimulation has ceased.
Repetitive high speed contraction
tetanic contraction
DBS: Double-burse stimulation
high frequency stimulation (tetanic)..lay off for a few seconds and then do it again
Ways of looking at contractions
forced transducers to look for AP
or just visual
Stimulation of the ulnar nerve stimulates what muscle? what does this result in when contracted
Adductor Pollicis- resulting in movement of the thumb forward and/or pinky finger twitch.
Places we can test a twitch reaction (4)
Ulnar nerve, ophthalmic branch of facial nerve, peroneal nerve, posterior tibial nerve
Facial nerve innervates the
Orbicularis oculi
A depolarizing block usually takes effect _____ and the effects last _______
Quick (few seconds)
a few minutes
TOF: With a non-dep block the twitches come back _____
in stages
A..then B…then C
TOF: with a non-dep block the first twitch is _____ and following twitches are _____
strongest
significantly weaker
A non-depolarizing block usually takes effect ______ and the effects last ____
after a few minutes
several minutes (~25min in the graph)
TOF: With a non-dep block we can use a _______ to physically measure the twitches and quantify the strength of twitches. The ratio is _____
forced transducer
B/A=TOF ratio
TOF: with a depolarizing block the twitches come back ____
at the same time but get stronger with time
In the later stages of recovery from a non-depolarizing muscle relaxant your train of four ratio will be near the value of _____
One (the closer that you are to B=A the closer the ratio will be to one)
What is the primary and secondary target of ACh release?
Primary: the ACh-R on the muscle
Secondary: the ACh-R on the motor neuron itself (puts acetylcholine back into the motor neuron)
Why is the first twitch of the TOF on the Non-depolarizing drug bigger/stronger than subsequent twitches?
non-dep drugs are antagonists and will block the ACh autoreceptor that is on the motor neuron which will slow down how fast VP1 is moved to VP2 position. The first twitch has had time to get VP2 into position. but subsequent twitches will have less ACh release bc of the inhibition of the autoreceptor.
How does a non dep drug affect the receptors?
Non depolarizing drugs are antagonists and will block the ACh-R on the muscle but also the ACh-R on the neuron.
How does a depolarizing drug effect the post synaptic cell? Why do the TOF twitches for a depolarizing drug come back at the same height/strength?
Depolarizing drugs affect the postsynaptic cell by keeping the ACh-R open causing prolonged depolarization.
The twitches come back at the same height/strength bc if the depolarizing drug is keeping the ACh autoreceptor open there should be plenty of ach release to move the VP1 to the VP2(ready release pool) position to release plenty of ACh.
The Non-dep drugs inhibit _______ whereas dep drugs have more effect on ______
Both sides of the synapse
the skeletal muscle
in a depolarizing block your twitches that are stimulated when measuring the strength of your block will be ______
About the same height/strength
ACh receptors of the motor neuron are called (3)
Alpha 3 Beta 2 receptor, Neuronal ACh receptors, Autoreceptors
VP1 transition to VP2 is activated by
the ion current of Sodium and Calcium through the ACh autoreceptors.
An ACh autoreceptor is stimulated by a both _____
ACh and depolarizing muscle relaxants
Succinylcholine is broken down by _____
plasmacholinestrases from the liver
When a non-depolarizing NMB binds to a ACh autoreceptor the receptor is _________
blocked but not activated; disrupting the replacement of the ready to use VP 2 vesicles
We have both P type and _______ Calcium channels on the presynaptic neuron on the NMJ. However, only the _______ calcium channels are required for action.
L-type; P-type
The _____ are supplementary Ca Channels. If you’re hungover and shaky from loads of alcohol from the night before you can take an _________ and that will settle the shaking down.
L type Ca channel
L type Ca channel blocker
A patient who has many immature nACh receptors on their skeletal muscle creates what main problem when utilization of succinylcholine?
They have a larger surface area of the muscle that is allowing potassium into the ECF
A more important muscle is more __________ to paralytic medications
resilient (requiring higher doses to paralyze things like your diaphragm)
Adductor pollicis vs diaphragm. which one is more sensitive to paralytics?
Adductor pollicis
The diaphragm has _____ ACh-R compared to the adductor pollicis
more
Your adductor pollicis muscle will start to be paralyzed at a ______ dose of NMB than your diaphragm
lower dose
The diaphragm is a ____ muscle and the motor neurons that affect the diaphragm come from spinal nerves ____, ____ and ___
skeletal
C3, C4 and C5
C3, C4, and C5 nerves combine to make the
phrenic nerve
Diaphragm innervation originates from
C3, C4, and C5 nerves (phrenic nerve)
What is the benefit of the diaphragm being controlled by the phrenic nerve?
the diaphragm is much lower than the phrenic nerve, the position of the phrenic nerve is beneficial because helps us protect being able to ventilate in the case of a spinal cord injury
T/F: If we have a spinal cord injury at T1, we would lose the ability to breath
False.
An injury above _____ in the spinal cord would cause damage that wipes out the ability to self ventilate.
C3
A spinal cord injury at C4 would cause ____
incomplete affect, will have some tone going to diaphragm but it will depend on the physical health of the person to determine if they will be able to survive that
After a patients receptors have been saturated with a neuromuscular blocker and we are waiting for the medication to wear off; would we see the diaphragm or the abductor pollicis muscle recover first?
Diaphragm
During a train of 4, the fourth twitch will disappear when ________ of the nACh receptors are blocked
~75-80%
During a train of 4 all of the twitches will disappear when ______ of the nACh-R’s are blocked
~90-95%
During a train of 4 the second twitch will disappear when ______ of the nACh-R’s are blocked
~90%
During a train of 4 the 3rd twitch will disappear when _______ of the nACh-R’s are blocked
~85%
When determining the strength of a paralytic dose with a train of 4 the _____ twitch is expected to cease first when an effective dose has been reached.
last/4th
After cessation of a case utilizing a NMB, we have stopped the paralytic. Which twitch would reappear first and what percentage of receptors would be free and unbound from the NMB.
The first of 4 twitches and there would be 5-10% of free nACh-R’s
Post-op if someone can lift their head off the bed we would expect that a max of ______ n-ACh-R’s are blocked
70%
We would utilize ______ mA on the nerve stimulator
50-80
Voltage
an electromotive force that can be applied to move a current.
When utilizing succinylcholine we lose potassium from the ICF; where does the potassium leave the cell from? (3)
1- Potassium Leak Channels (loses highest amount here)
2- Potassium VG channels
3- ACh Receptors
When utilizing succinylcholine we would expect movement of what ions?
Sodium and Calcium(small amount) into the cell
Potassium out of the cell
We have ____ motor neurons per _____ muscle cell except for in the _____ muscle.
one
one
eye
What would happen in regards to Ca if we give a depolarizing muscle relaxer and have lots of fetal ach receptors.
Ca would be able to come into the cell in higher amounts
Utilizing a depolarizing muscle relaxant can increase intraocular pressure. Why?
The eye muscles are relatively small muscles that are innervated by multiple neurons. This increases the space of NMJ and is significant to the size of the muscle. Activation of these receptors with a depolarizing agent increases Na and Ca influx, increasing IOP.
Inhibitory neurotransmitters in the CNS/spinal cord (2)
GABA
glycine
GABA (gamma-aminobutyric acid) increases permeability to
Chloride (Cl-)
Acetylcholine in the CNS causes
increased awareness/excitation
If we have something that blocks ACh within the CNS we would have what side effects?
Sleeeeepy.
Awareness in the CNS achieved by ACh occurs at what type of receptors?
muscarinic ACh Receptors
A drug that effectively blocks mACh receptors
Benadryl/diphenhydramine
Benadryl could be considered antihistamine and ________. The side effects would be _____ and _____
Anticholinergic.
Drowsy and increased HR (bc it can also affect the mACh-R at the heart)
If we inhibit acetycholinesterase that should
increase awareness/wake us up
In the OR, usually, a useful Acetylcholinesterase inhibitor does not ______ because ______
cross the blood brain barrier
we don’t want them to wake up
Why do we prescribe stigmines for Alzheimers?
Because stigmines are a centrally acting acetylcholinesterase inhibitor that can cross the BBB and enhance the Ach activity at the mACh-R
Acetylcholinesterase inhibitor side effects (3)
- reverse paralytic/increase awareness (if crossed BBB)
2- Decrease HR
3- increased secretions (bad if we have increased secretion in lungs)
Histamine is considered
excitatory
Glutamate is considered
stimulatory/excitatory
Someone that does methamphetamine, they have increased awareness because _____
glutamate mediates some of the drug activity and it is excitatory
Excessive amount of glutamate can damage
The CNS
Dopamine inhibits
motor activity
Parkinson’s patient lack normal amounts of ________ causing tremors
dopamine
Norepinephrine in the CNS is considered
excitatory
Antidepressants are typically ______ inhibitors and they are also sometimes used for _______
Nor epi reuptake inhibitors.
Chronic pain
The following neurotransmitters increase awareness in CNS (4)
1- Acetylcholine
2- Histamine
3- Glutamate
4- Norepi
The following neurotransmitters decrease activity/awareness in the CNS
1- GABA
2- Glycine
3- Dopamine
A lower pH ______ CNS activity while a higher pH ________ CNS activity. These effects have to do with ____
Decreases; increases
Calcium
An acidotic patient has a high CO2. Why?
A high concentration of H+ is buffered with HCO3 in the body. They combine to make H2CO3. This carbonic acid then disassociates into CO2 and H2O. Thus a lower pH = Higher CO2 levels
Albumin is typically ________ charged
negatively charged
Which has a higher affinity for albumin; calcium or H+
H+
A lower pH is the result of free floating _____ this displaces ______ from albumin causing CNS _______
H+; Calcium; depression
A higher pH means there is less free floating _____ this allows calcium to bind to ______ causing CNS _____
H+; Albumin; Excitation
Prolonged hyperventilation causes ______pH and overall less ______ which could lead to _______
Increased pH; less H+; CNS excitation and even seizure
