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