Lecture 10/4 - Refelxes pt 2 Flashcards
Test 2
What happens to our fetal nAch-R as we grow?
They are swapped out for Adult nAch-R
When there’s a problem with contracting skeletal muscle, what will our body do to fix that?
Add more nAch-R
Describe these areas in the post synpase:
Junctional area
Perijunctional area
Postjunctional area
Junctional: Center, right under clefts
Perijunctional: on the side, side of clefts
Postjunctional: on the side of perijunctional
Where should nAch-R be?
NMJ - junctional area only.
Where can fetal nAch-R appear in skeletal muscle?
NMJ in the junction, perijunctional, and postjunctional areas
What are ways to assess neuromusclar activity?
TOF
Single Twitch
PTC (Post-tetanic count)
DBS (Double burst stimulation)
What muscle does the ulnar nerve activate?
Adductor Pollicis
Define the Supramaximal Stimuli
Voltage strong enough to fully recruit all motor neurons and fully activate the skeletal muscle cells
What happens if you dont get a twitch at all?
Not enough voltage or something wrong at the NMJ
What is TOF?
Train of Four
Repetitive stimulation at 2hz/2sec
Ex) 2 secs = 4 twitches
4 secs = 8 twicthes
Define tetanic
Contractions when stimulated at a high frequency repeatedly
What is post-tetanic count?
Number of contracts after tetanic contraction
Helps determine health of the synapse
Increases PTC = light block
Decreases PTC = deep block
What is DBS?
Double Burst Stimulation
2 short burst of 3 electrical stimuli at 50 Hz with brief pause in between
What is the Hz with DBS?
50 Hz
What happens if you stimulate the ulnar nerve and get a really big contraction?
Block is not deep enough
What happens if stimulate the ulnar nerve and get no contraction?
Deep block
What happens while stimulating a nerve?
Electrons depolarize the outside which changes the polarity of the outer cell…
This indirectly depolarizes the inside of the cell causing an AP and muscle contraction
What fingers muscles are affected and what fingers move when the ulnar nerve is stimulated?
Adductor Pollicis
Thumb twitches forward
Pinky twitches
one or both will happen
What will happen if you are completely paralyed and the ulnar nerve is stimulated in TOF?
Nothing - no twitches
What are some alt sights for nerve stimulation if you cant use ulnar nerve?
Ophthalmic branch of Facial Nerve (outer side of eye socket)
Peroneal nerve (butt)
Posterior tibial nerve (lower extremity)
T/F: Depolarizing blocks have a short half life
T
Onset/Half life nondepolarizing block:
Few minutes
lasts extremely long
Onset/Half life depolarizing block:
quick
short lasting
In TOF responses: Which twitch is A? B?
1st twitch = A
Last = B
What is the TOF ratio?
B/A
What does a higher TOF ratio mean?
drug is wearing off
Which paralytic can you have a TOF ratio in?
Nondepolarizing Block
T/F: In TOF, all 4 twitches will be the same height and highest as before you give the drug
T
In TOF responses: which twitch is often the strongest?
1st
A
In TOF responses: what does the 4 twitches being different heights mean?
Incomplete block
T/F: In TOF responses: The twitches all come back at the same rate as the drug wears off
F
The twitches come back in different stages
What is the TOF ratio in depolarizing block? Why?
1
All the twitch as the same size because this is a complete block
Describe an Alpha-3 Beta-2 Receptor
nAch-R on motor nueron = autoreceptor
3 alpha subunits; 2 beta subunits
What does the Alpha-3 Beta-2-R do?
When activated by Ach, Na+ and Ca++ flows in.
This moves VP1 vesicles towards to to synapse and VP2 vesicles to the membrane for exocytosis
What is Succs broken down by?
Plasma Cholinesterase
Nondepolarizing blockers inhibit ________of the synapse
both sides
Depolarizing blockers inhibits _________ of the synapse
more of the skeletal muscle side
What are the L-type Ca++ channel’s role in the motor neuron?
Supplement the P-Type
Faster than P-type
What type of drug can you give an alcoholic who has tremors?
CCB
If you give an _______ dose of CCB you will not paralyze them
High
What happens when you give Succs with fetal nAch-R present?
Prolonged depolarization in MULTIPLE areas
Increased K leaving the cell.
Vfib
What are the nerves called that connect to the diaphragm?
Phrenic nerves
Where do the phernic nerves originate and connect to the diaphragm?
C3, C4, C5
Where does Adductor Pollicis inhibition start?
20 micrograms/kg
Where does Adductor Pollicis have total inhibition?
40 micrograms/kg
T/F: If there are 4 strong twitches in the adductor pollicis, pt can probably breath on their own.
T
PROBABLY
Where does Diaphragm inhibition start?
40 micrograms/kg
Where does Diaphragm have total inhibition?
90 micrograms/kg
In less important muscles: They are the ____ to be paralyzed and the _____ to recover.
1st
Last
In more important muscles: They are the _____ to be paralyzed and the ______ to recover.
Last
1st
What type of neuromusclar blocker are you generally using TOF for?
Non depolarizing
In TOF: What happens when the 4th twitch disappears?
75-80% of nAch-R blocked
In TOF: What happens when the 3th twitch disappears?
85% of nAch-R blocked
In TOF: What happens when the 2th twitch disappears?
85-90% nAch-R blocked
In TOF: What happens when the All twitches disappears?
90-95% nAch-R blocked
If the patient is coming out of a block and can lift their head, what can we assume?
All 4 twitches are present
Maybe able to breathe on their own
What are your stimulator settings (TOF Voltage)?
50-80 mA
Define voltage
Force/push stimulator applies
T/F: Your stimulator settings is equal to the supramaximal stimuli
T
What additional aspect is needed to cause contractions with fetal nAch-R when using Succs?
Bad motor deficits
Why does Succs cause an increase in IOP?
IOP = intraocular pressure
Ocular muscle is controlled by mulitple motor neurons = multiple NMJ
Ca++ coming in causes contractions which increases the pressure
What can happen with increased IOP?
Blindness
Describe GABA
inhibitory neurotransmitter in CNS
increases Cl- conductance
What happens if you suppress GABA?
uncontrolled activity of CNS —> seizures
Describe Gylcine
inhibitory neurotransmitter in CNS
Similar to GABA
Very important in spinal cord
What are the 2 main neurotransmitters in the CNS/spinal cord?
GABA
Glycine
What neurotransmitters increase alertness and awareness?
Ach
Histamine
Glutamate
NE
What is the neurotransmitter in the PNS?
Ach
Anticholinergics block ____ and cause _______
Ach
Drowsiness
What type of drug is Benadryl? What can a large dose do?
Central histamine and central anticholinergic
Increase heart rate d/t mAch-R in the heart
What happens if you inhibit Ach-ase?
Increase alertness/awareness
What types of drugs can we give to reverse a paralytic without waking the patient up?
Drugs that inhibit Ach-ase that DO NOT cross the BBB
NOT -STIGMINES
What is the main neurotransmitter for pain?
Glutamate
What does too much glutamate cause?
Brain cell death
What drug Tx Parkinsons?
Dopamine
What is dopamine?
Potent motor inhibitor
What are 3 inhibitory neurotransmitters?
GABA, Dopamine, Glycine
What were NE reuptake inhibitors used for?
Chronic pain
What does severe acidosis do?
decrease CNS activity
What does severe alkalosis do?
increase CNS activity
How are Acid-Base imbalances related to Ca++?
Albumin is largely present in blood plasma & negatively charged
-The less H+ ions = The more Ca++ the albumin will attract
This means less free Ca++ in the blood stream = increased CNS activity (alkalosis)
-The more H+ ion = less Ca++ the albumin will attract
This means more free Ca++ in the blood = decreased CNS activity (acidosis)
Hypoventilate =
increase H+
Hyperventilate =
decrease H+
