Neuroscience: Nmj

Front 1

What is controlled by the gamma motor neuron?

Back 1

The muscle spindle

Front 2

What is the fusimotor system?

Back 2

The muscle spindle and the associated gamma motor neuron

Front 3

What is the function of the gamma motor neuron?

Back 3

To give proprioceptive feedback

Front 4

In a reflex, which muscle is stimulated and which is inhibited?

Back 4

The extensor is stimulated while simultaneously the flexor is inhibited.

Front 5

What NT is used to inhibit a skeletal muscle movement in a reflex?

Back 5

GABA

Front 6

What interneuron of the CNS controls excitability of motor neurons?

Back 6

Renshaw cells

Front 7

What NT is used by Renshaw cells?

Back 7

glycine

Front 8

What drug can be used to block glycinergic synpases of the Renshaw cell?

Back 8

Strychine

Front 9

Why does strychine cause spastic paralysis and convulsions?

Back 9

Blocks the regulatory effects of Renshaw cells, allowing uncontrolled excitability (tetanus) of motor neurons.

Front 10

How does strychine cause death?

Back 10

Spastic paralysis of respiratory muscles

Front 11

What is a motor unit?

Back 11

Alpha motor neuron with all of the muscle fibers it innervates

Front 12

Where are the t-tubules located in the sarcomere?

Back 12

in plane with the Z disk

Front 13

What depolarizes the T-tubule membrane?

Back 13

Action potential propagated through Na channels

Front 14

What causes hydropyridine receptors to change the conformation of the ryanodine receptors?

Back 14

Depolarization

Front 15

What does Ca bind once in the muscle?

Back 15

Troponin: allowing binding sites for myosin on actin.

Front 16

How is ACh loaded into vesicles?

Back 16

Using a vesicle transporter

Front 17

What drug is able to block nicotinic ACh receptors?

Back 17

Curare

Front 18

What drug is able to block muscarinic ACh receptors?

Back 18

Atropine

Front 19

What type of ions are able to pass through a nicotinic ACh receptor?

Back 19

Na/K
It is a non-selection cation channel

Front 20

What type of channel is the nicotinic ACh receptor?

Back 20

Ionotropic ligand-gated non-selective ion channel

Front 21

What causes vesicle mobilization in the axon terminal?

Back 21

Calcium entry from depolarized voltage-gated calcium channels

Front 22

What NT is released into the NMJ?

Back 22

ACh

Front 23

What receptors are present on the motor end plate?

Back 23

nicotinic ACh receptors

Front 24

What generates the endplate potential?

Back 24

Activation of the nicotinic receptors

Front 25

What initiates an action potential in the sarcolemma?

Back 25

EPP

Front 26

What breaks down the ACh after EPP has been produced?

Back 26

Actylcholine esterase

Front 27

How is choline retrieved?

Back 27

Na/Choline transporter

Front 28

What carries the action potential throughout the muscle tissue?

Back 28

T-tubules

Front 29

How is the ryanodine receptor activated?

Back 29

Calcium-induced-calcium-release

Front 30

What moves the tropomyosin to uncover myosin binding sites on actin?

Back 30

Calcium binding to troponin forces a conformational change that moves tropomyosin.

Front 31

What toxins effect SNARE proteins and vesicle fusion?

Back 31

Botulinum and tetanus toxin

Front 32

What is Lambert-Eaton myasthenic syndrome?

Back 32

Autoimmune disorder that leads to a loss of voltage-gated presynaptic Ca channels

Front 33

Why are the amplitudes of MEPPs unaffected in myasthenic syndrome?

Back 33

MEPPs are not calcium dependent.

Front 34

What is myasthenia gravis?

Back 34

Autoimmune disorder characterized by the antibodies blocking nACh receptors on post-synaptic neuron.

Front 35

What nerves are typically effected by myasthenia gravis?

Back 35

Cranial nerves

Front 36

What drug intervention can be used to treat myasthenia gravis?

Back 36

acetylcholinesterase inhibitors

Front 37

Which myasthenic disorder (gravis or syndrome) will have affected MEPPs?

Back 37

Myasthenia gravis: reduction in nACh receptors

Front 38

Which myasthenic disorder effects the depth of the junctional folds (gravis or syndrome)?

Back 38

Myasthenia gravis: reduction in junctional fold and an increase in synaptic space

Front 39

What is the difference is paralysis associated with botulinum and tetanus toxin?

Back 39

Botulinum toxin causes flaccid paralysis
Tetanus toxin causes spastic paralysis

Front 40

What protein is targeted by tetanus toxin?

Back 40

synaptobrevin on GABA/glycine vesicles

Front 41

What toxin target NMJs?

Back 41

Botulinum

Front 42

What proteins are targeted by botulinum?

Back 42

Synaptobrevin
Syntaxin
SNAP-25

Front 43

What bacteria produces tetanus toxin?

Back 43

Clostridium

Front 44

What toxin would cause the loss of synaptic inhibition on spinal motor neurons?

Back 44

Tetanus toxin

Front 45

What toxin would cause inhibition of ACh release into the NMJ?

Back 45

Botulinum toxin

Front 46

What toxin would cause hyper-excitation of skeletal muscles?

Back 46

Tetanus

Front 47

What bacteria produce botulinum toxin?

Back 47

Clostridium

Front 48

What venoms cause the complete depletion of ACh?

Back 48

Black widow and scorpion venom

Front 49

What is the effect of tetrodotoxin and what animal produces it?

Back 49

Blocks Na channels
Produced by the puffer fish

Front 50

What animal toxin can bind specifically to ACh receptors?

Back 50

Cobra toxin

Front 51

What is the action of the alpha bungarotoxin?

Back 51

Irreversibly binds nicotinic ACh receptors

Front 52

What is the effect of conotoxin?

Back 52

blocks Ca channels
blocks Na channels
blocks glutamate receptors
blocks ACh receptors

Front 53

What is the effect of Tabun, Soman and Saran nerve gases?

Back 53

They block the action of acetylcholinesterase

Front 54

What drug is used to reactivate the acetylcholinesterase activity following nerve gas exposure?

Back 54

3-PAMC1