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Flashcards in Nueromuscloskeletal Deck (37):
0

Motor neuron and muscle communicate via activation of _____ on ____

Nicotinic acetylcholine receptors
Muscle cells

1

Acetycholinesterase

Breaks down acetylcholine to choline and acetate
Made by both muscles and neurons

2

Choline Acetyltransferase

Synthesizes acetylcholine from choline + acetyl-CoA in the cytoplasm

3

Acetylcholine is transported into synaptic vesicles via ____

Acetylcholine/H+ antiporter

4

Proteoglycan that interacts with muscle specific kinase (MuSK) to trigger muscle cell to maintain clustered nicotinic acetylcholine receptors in area beneath neuronal contact

Agrin

5

Protein critical in formation of normal neuromuscular junctions and re-establishing neuromuscular junction following damage

Agrin

6

Kinase found in myocytes that helps with dispersal of nAChR clusters that have not been innervated by a motor neuron. ACh activation of nAChR helps to activate the kinase

Cyclin Dependent Kinase 5

7

Voltage gated Ca channels are localized ____

near the active zone in the presynaptic membranes

8

Endplate potential

Muscle cell response measured as local graded depolarization

9

Alpha subunits of nicotinic acetylcholine receptor

Binding of 2 ACh molecules --> channel open and increase membrane permeability to cations --> muscle membrane depolarization

10

Cholinergic agonists: binds to nAChR --> channel activation
Cause muscle spasms

Carbachol, nicotine

11

Blocks neuromuscular transmission by binding to nAChR, preventing ACh from binding and activating the receptor. Does not interact w/ voltage-gated channels involved in action potentials

Curare

12

Inhibit activity of acetylcholinesterase --> prolingation of endplate depolarization

Neostigmine, physostigmine, DFP

13

Prevents re-uptake of choline by presynaptic terminals and eventual depletion of releasable ACh --> paralysis

Hemicholinium-3

14

Subunit composition of adult nAChR

alpha2 beta gamma epsilon

15

Neuromuscular junction comprised of 3 cells

motor neuron
muscle fiber
Schwann cell

16

Ca2+ in the muscle is stored and released from ____

Terminal cisternae of the sarcoplasmic reticulum

17

Voltage gated Ca2+ channel that's a voltage sensor on the T Tubule

Dihydropyridine receptor (DHPR)

18

Receptor on terminal cisternae of sarcoplasmic reticulum that is linked to dihydropyridine receptor on T tubule

Ryanodine receptor
Lets a lot of Ca out

19

Junctional tetrad is formed by

Dihydropyridine receptor and ryanodine receptor

20

SERCA

Ca2+ ATPase on SR membrane that pumps Ca2+ back into SR
Maintains low cytoplasmic concentration of Ca2+
Causes muscle relaxation

21

Calsequestrin

In sarcoplasmic reticulum
Low affinity but high binding capacity for Ca2+
Binds Ca2+ to keep [free Ca2+] low
Easily releases Ca2+ when concentration in lumen of cisternae decreases

22

Alignment protein of thick filaments

Titin

23

Alignment protein for thin filaments

Nebulin

24

Thin filament

Actin, tropomyosin, troponin

25

Thick filament

Myosin

26

Rigor mortis is caused when

myosin crossbridge stays bound to actin when depleted of ATP

27

Rate limiting step of crossbridge cycle

ADP release from myosin head

28

Myosin state(s) that have high affinity for actin

Unbound myosin
Myosin-ADP+P

29

Myosin state that has low affinity for actin

Myosin-ATP

30

Contraction where force is generated by muscle but no shortening of muscle fibers

Isometric contraction

31

Contraction where load is help constant and shortening of muscle fibers occurs

Isotonic contraction

32

Contraction where muscles relax against a load

Eccentric contraction

33

Troponin

Binds 4 Ca2+

34

Troponin T

Binds tropomyosin

35

Troponin C

Binds Ca2+

36

Troponin I

Binds actin