ECC_Muscle Phys

Question 1

Choline acetyltransferase

Answer 1

synthesizes ACh from choline and acetyl coA

ACh brought in by ACh-H+ exchanger

Question 2

Synaptobrevin

Answer 2

V-SNARE

complexes with SNAP-25 and syntaxin (t-SNAREs) to drive vesicle toward the synaptic membrane

Question 3

Synaptotagmin

Answer 3

Ca receptor of synaptic vesicle that detects influx of Ca and triggers exocytosis

Question 4

Tetanus and botulinum BDFG

Answer 4

target synaptobrevin

Question 5

Botulinum A and E

Answer 5

target SNAP25

Question 6

Botulinum C1

Answer 6

syntaxin

Question 7

Mini End plate potential (MEPP)

Answer 7

spontaneous Vm fluctuations similar to normal EPPs caused by the spontaneous release of 1 vesicle load of ACh

Question 8

Actin binding site

Answer 8

on MHC for cross bridge formation

Question 9

ATPase binding site

Answer 9

for binding and hydrolysis of ATP

Question 10

F actin

Answer 10

backbone of thin filament

Question 11

SERCA

Answer 11

primary means of bringing Ca back into the SR to facilitate relaxation

Question 12

Calsequestrin

Answer 12

binds Ca in the SR to prevent elevated Ca from inhibiting SERCA proteins thereby facilitating relaxation

Question 13

Vmax

Answer 13

max velocity of contraction dependent on myosin ATPase
Velocity decreases as mass increases
INDEPENDENT OF LENGTH

Question 14

Asynchronous recruitment

Answer 14

multiple fiber summation where CNS alternates MUs that are active to delay fatigue in submaximal contractions

Question 15

size principle

Answer 15

progressive recruitment of small MUs –>larger MUs (i.e. smaller MUs will have larger EPSPs at a give stimulus)

Question 16

Muscle fiber types

Answer 16

TI=Slow twitch TII= Fast

differ in in isoform of myosin heavy chain mATPas

Question 17

Slow twitch fibers

Answer 17

Slow oxidative Type I
small CSA high oxygen transport for oxphos–> high cap density, high myoglobin, low glycogen
slow contractions, resistant to fatigue

Question 18

Type IIA

Answer 18

Fatigue resistant
oxidative metabolism
high myoglobin, mitochondria, high glycogen, fatigue resistant, fast contraction

Question 19

Type IIX/B

Answer 19

Fatigue, high glycolysis, few mito, few myoglobin, white

Question 20

Primary sensory endings

Answer 20

of group Ia axons innervate bag fibers to detect changes in length
involved with stretch reflex

Question 21

secondary sensory endings

Answer 21

of group II axons innervate chain fibers to detect static length

Question 22

Autogenic inhibition

Answer 22

activation of GTO Ib axons which inhibit the agonist and activate the antagonist

**protective

Question 23

nAChR subtypes

Answer 23

vary by location (skeletal bs. neuronal, CNS)

allows for specificity of drug targets

Question 24

Tetrodotoxin

Answer 24

from puffer fish, inhibit v-gated Na channels to prevent axonal conduction in the motor neuron as well as in the muscle

Question 25

Local anesthetics

Answer 25

inhibit v-gated Na channels to prevent axonal conduction

blocks motor activation AND sensory signals

Question 26

Curare alkaloids

Answer 26

competitive nAChR antagonists that causes muscle paralysis during anesthesia

Question 27

Succinylcholine

Answer 27

depolarizing nAChR agonist causes paralysis during anesthesia

Question 28

Cholinesterase inhibitors

Answer 28

bind and block AChE
increase ACh in the NMJ
use for dementia w/ Alz or Parkinson, MG
also found in Sarin gas

Question 29

Dantrolene

Answer 29

inhibits RYR and blocks release of Ca to decrease muscle activation
tx for malignant hyperthermia, spasticity