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.