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Year2 MSK exam 1 > MSK phys > Flashcards

MSK phys Flashcards

(90 cards)

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1
Q

toxin in puffer fish

A

tetrodoxin

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2
Q

what is given to Tx tetrodoxin poisoning

A

activated charcoal to bind it up

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3
Q

how does tetrodoxin work

A

block V Na Channels
inhibits depolarization
AP generation/propagation inhibited

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4
Q

blockage of K leak channels would do what

A

hypopolarize RMP

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5
Q

what toxin is in mamba snakes

A

dendrotoxin

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6
Q

how does dendrotoxin work

A

blocks V K channels so blocks hypopolarization

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7
Q

effects of dendrotoxin on Ach release

A 
inhibit repolarization
prolonging AP
prolonged Ca influx at nerve terminal
enhanced ACh release
hyperexcitability and convulsive Sx
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8
Q

inheritance of malignant hyperthermia

A

autosomal dominant

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9
Q

what can trigger malignant hyperthermia

A

volatile anesthetics and some muscle relaxers

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10
Q

what causes malignant hyperthermia

A

uncontrolled release of Ca from SR leading to tachy, rigidity, hyperventilation and hyperthermia
acute hypermetabolic state in muscle tissue leading to prolonged contraction

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11
Q

what R is affected in malignant hyperthermia

A

RYR1

also could be dihydropyridine R

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12
Q

where is RYR located

A

SR membrane

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13
Q

what are the L type Ca channels and where are they located

A

DHPR

T tubule membrane

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14
Q

role of DHPR

A

voltage sensor

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15
Q

role of Ca in skel mm tension

A

removes regulatory protein tropomyosin from actin so there can be cross bridge formation

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16
Q

what is directly proportional to tension production in skel mm

A

number of cross bridges

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17
Q

what is required for muscle relaxation to occur

A

removal of Ca from sarcoplasm

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18
Q

is ATP needed for muscle relaxation or contraction

A

relaxation

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19
Q

where is the ATPase binding site

A

on myosin head

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20
Q

what is the pump to remove Ca from sarcoplams for skel mm relaxation to occur

A

SERCA the sarcoplasmic and endoplasmic reticulum Ca ATPase

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21
Q

AutoAb are against what in myasthenia gravis

A

nAChrR

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22
Q

initial mm affected in myasthenia gravis

A

extraocular mm
bulbar (speech swallowing)
neck
proximal limb muscles

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23
Q

Ach binding to R on motor end plate cause what

A

opening of ligant gated ion channels

depolarization end plate between Na and K

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24
Q

effect of EPP on adjacent sarcolemma of skel m

A

V Na Channels open and AP generated

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25
enzyme that degrades Ach in NMJ
acetylcholinesterase
26
what enzyme synthesizes Ach
choline acetyltransferase
27
what drives Ach uptake into vesicle
vesicular proton elctrochemical gradient (+ voltage and low pH inside)
28
Where is Ach made
nerve terminal
29
what allows for Ach uptake by vescile
ACh- H+ exchanger in ACh out H+
30
endrophonium (tensilon) test
give AChEI and see if improve Sx
31
why does an ice pack help in myasthenia gravis
inhibits AChE activity
32
two major clinical forms of myasthenia gravis in eyes
ocular MG: only ocular Sx | general MG: generalized weakness
33
why does MG attack eyes frist
fewer ACh R in eye muscles high rate firing in eye motor neurons lower quantal release ACh per event
34
+ SCC EMG increase uppon repeated activation autoAb found against V Ca Ch Dx
lambert eaton myasthenic syndrome | paraneoplastic
35
where does LEMS attack
presynaptic VCaCh | decrease ACh vesicle fusion and exocytosis
36
Which vesicle protein is a Ca sensor
synpatotagmin
37
conotoxin is from what
marine cone snail
38
how does conotoxin work
blocks N type VCa ch | analgesic
39
botulism affects what in NMJ
impaired ACh vesicle fusion
40
what other toxin (not botulinum) blocks the ACh release
tetanus toxin
41
why does botulinum toxicity take a while to reverse after given anti toxin
``` need synaptobrevin (v SNARE) and sNAP 25 (t SNARE) to be newly synthesized ```
42
which botulinum attack SNAP 25
A and E
43
which botulinum attack synaptobrevin
B D F G
44
what causes spastic paralysis seen in tetanus
central effects bind NMJ presynaptic membrane and retroaxonally transported to SC NT release is blocked impact spinal INHIBITORY interneurons
45
what type of paralysis does botulinum toxin cause
flaccid
46
RMP
-70mV
47
what medications promote cellular uptake of K
epinephrine, insulinm, aldosterone
48
cell death can result in what metabolic state
hyperkalemia
49
what occurs to membrane with highger K efflux
hyperpolarization
50
what occurs with a decrease in ECF K
more K efflux, hypokalemia
51
what occurs with an increase in ECF K
dec K efflux, hyperkalmia | membrane potential less negative aka depolarized
52
RMP most sensitive to what ion [ ]
K
53
When is K permeability the highest
relative refractory period of Na channels
54
methods of removal of NT from synaptic cleft
enzymatic breakdown, cellular uptake, diffusion
55
NMJ are excitatory/inhbitory or both
always excitatory EPP
56
how is inhibition of skel mm achieved
CNS through IPSPs at dendrites and cell body of motor neuron
57
what are the active zones of NMJ
dense spots where synaptic vesicles are clustered | oriented over postjunctional folds
58
what are postjunctional folds
extensive invaginations on postsynaptic membranes under nerve terminal increase SA of muscle plasma membrane
59
what is time delay in impulse transmission with Ach diffusion
50 nm
60
What is synaptotagmin
Ca R of synaptic vesicles | detect rise in Ca and trigger exocytosis of docked vesicles
61
synaptobrevin forms a complx with what
SNAP 25 and syntaxin
62
botulinum toxin C1 blocks what
cleaves syntaxin
63
what are sarcomeres
actin and myosin units | Z line to Z line
64
What is the A band
myosin (thick filament)
65
What is the H zone
middle of A band (part where does not overlap with thin actin)
66
what is the M line
center of A band
67
what is the I band
part of ACtin not overlapping with myosin
68
what is the Z line
thin filament attachment
69
what is a thick filament
2 myosin heavy chains and 4 light chains
70
what are the regions of the myosin heavy chains
rod (tail) hinge (arm) head (cross bridges)
71
what are the 4 light chains in thick filament
``` 2 alkali (essential) 2 regulatory ```
72
What are the binding sites on myosine heavy chains
actin binding site for cross bridge formation | myosin ATPase site for hydrolyzing ATP
73
What is F actin
filamentous- backbone | double stranded alpha helical polymer of actin molecules
74
what are the actin binding proteins
tropomyosin | troponin
75
tropomyosin blocks what at rest
myosin binding site on actin
76
tropomyosin interacts with how many actin monomers
7
77
tropinin interacts with what
1 tropomyosin molecule and actin
78
torponin T
binds single tropomyosin molecule
79
troponin C
binds Ca
80
troponin I
binds actin and inhibits contraction
81
what happens when Ca binds troponin
tropomysoin slips away from blocking position allowing for cross bridging to occur
82
how do AP propagate from sarcolemma to interior of muscle fibers
transverse tubules
83
What is the triad in skel mm propagation
SR cisternae on 2 sides of T tubule that allow for propagation of AP
84
Channels needed to propagate AP
DHPR- t tubule | RYR- SR
85
DHPR are found in clusters of how man
4 needed for conformational change allowing Ca release
86
do you need Ca release to activate RYR
no, mechanical from DHPR
87
high Ca in SR causes what
inhibits activity of SERCA
88
what delay inhibition of Ca pump activity
Ca binding proteins in SR lumen (increase Ca amount in SR)
89
what are the Ca binding proteins in SR
calsequestrin localized in SR at triad junction complexes with RYR
90
what is calreticulin
Ca binding protein in smooth muscle

Year2 MSK exam 1 (26 decks)

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