Neuromuscular Control

Question 1

What structure in the muscle carries the action potential?

Answer 1

T-tubules

Question 2

Where are small molecule neurotransmitters made?

Answer 2

in the nerve terminal

Question 3

Cocaine blocks the reuptake of ____ and ____.

Answer 3

dopamine; norepinephrine

Question 4

_____ neurons innervate skeletal muscle and are considered motor neurons.

Answer 4

Somatic

Question 5

What is a motor unit?

Answer 5

the motor neuron and all the fibers it innervates

Question 6

Lidocaine is a _____ channel blocker.

Answer 6

voltage-gated Na+

Question 7

What happens to the EPP in patients with myasthenia gravis?

Answer 7

the EPP may not trigger an action potential

Question 8

Your patient comes in complaining of overall muscle weakness. You give her an injection of tensilon and she performs activities much better. Why is this?

Answer 8

tensilon is an acetylcholinesterase inhibtor, meaning it increases the amount of acetylcholine in the synapse; your patient likely does not typically have as much acetylcholine, so the injection increased the amount available to her for her body to use for muscle contractions

Question 9

How is acetylcholine removed from the synaptic cleft?

Answer 9

acetylcholinesterase

Question 10

The depolarization of Na+ causes what to happen?

Answer 10

the voltage-gated Na+ channels open (allowing even more Na+ in) and the action potential is propagated in the muscle fiber

Question 11

____ allow the neurotransmitters to leak out of their vesicle and exit out of the reuptake channels and accumulate in the synapse.

Answer 11

Amphetamines

Question 12

Does caffeine increase or decrease the production of cAMP?

Answer 12

increase (increases neuronal excitability)

Question 13

Nicotine is an ____ to the acetylcholine nicotinic receptor channel; Curare is an ____ to the receptor.

Answer 13

agonist (+); antagonist (-)

Question 14

Why must the neurons make the synthetic enzymes themselves?

Answer 14

because the neurotransmitters are made directly in the nerve terminal

Question 15

What happens when the DHPR receptor contacts RyR1 on the sarcoplasmic reticulum?

Answer 15

calcium is released

Question 16

_____ synthesizes acetylcholine; ____ breaks it down.

Answer 16

cholineacetyltransferase; acetylcholesterase

Question 17

How are the actions of neurotransmitters terminated?

Answer 17

1. transported into glial cells
2. inactivating enzymes
3. diffuse out of the synaptic cleft into blood, etc.
4. packaged back into a vesicle on cleft via transporters

Question 18

Blocking the voltage-gated Ca2+ channel ___ muscle contraction.

Answer 18

inhibits

Question 19

Tensilon is an _____ inhibitor.

Answer 19

acetylcholinesterase

Question 20

What agent blocks Ca2+ channels and prevents muscle contraction?

Answer 20

Conotoxin

Question 21

____ cells are supporting cells of the brain that reuptake neurotransmitters transported out of the synaptic cleft.

Answer 21

Glial

Question 22

What ion causes an end-plate potential (EPP) on the Ach nicotinic receptors?

Answer 22

Na+

Question 23

Blocking the neuronal Na+ channel ___ muscle contraction.

Answer 23

inhibits

Question 24

____ neurons are motor neurons that carry messages away from the CNS.

Answer 24

Efferent

Question 25

Dystrophin acts as a structural protein to hold the ____ together.

Answer 25

sarcomere

Question 26

Calcium-induced calcium release (CICR) causes what to happen?

Answer 26

calcium goes on to bind to an adjacent ryanodine (RyR1) receptor and release more calcium

Question 27

When can EPPs open voltage-gated Na+ channels?

Answer 27

after every potentiation/stimulation

Question 28

Tetrodotoxin, Conotoxin, Tubocurarine, and botulinum toxin all _____ muscle contraction.

Answer 28

decrease

Question 29

What agent inhibits acetylcholine release and prevents muscle contraction?

Answer 29

Botulinum toxin

Question 30

What structure of the muscle is a calcium reservoir?

Answer 30

sarcoplasmic reticulum

Question 31

Acetylcholine, Nicotine, and Physostigmine all ____ muscle contraction.

Answer 31

increase

Question 32

If the neuron releases glutamine, it is classified as _____.

Answer 32

glutamatergic

Question 33

If the neuron releases dopamine, it is classified as ____.

Answer 33

dopaminergic

Question 34

What agent blocks neuronal Na+ channels and prevents muscle contraction?

Answer 34

Tetrodotoxin

Question 35

Calcium induces muscle contraction via interaction of ___ and ___.

Answer 35

myosin; actin

Question 36

What is a graded response?

Answer 36

the transient EPSP or IPSP responses that come in from the dendrites

Question 37

Which receptors are activated by the influx of calcium into the terminal button and subsequent release of acetylcholine?

Answer 37

nicotinic receptors

Question 38

____ is an enzyme that deactivates acetylcholine in the synaptic cleft.

Answer 38

Acetylcholinesterase

Question 39

How is calcium in muscle transferred back into the sarcoplasmic reticulum?

Answer 39

SERCA pump (sarcoplasmic reticulum calcium ATPase)

Question 40

Are the actions of nerve gas permanent?

Answer 40

YES - you would die

Question 41

If the neuron releases GABA, it is classified as ____.

Answer 41

GABAergic

Question 42

Nerve gas and some insecticides inhibit acetylcholinesterase, which allows the buildup of what?

Answer 42

acetylcholine (allowing constant muscle contraction)

Question 43

Acetylcholinesterase breaks acetylcholine down into ___ and ___.

Answer 43

choline; acetic acid

Question 44

Does the action potential only happen in the axon?

Answer 44

YES

Question 45

Serotonin, histamine, dopamine, norepinephrine, and epinephrine are all ____-molecule neurotransmitters.

Answer 45

small

Question 46

_____ affect dopaminergic, noradrenergic, and serotonergic neurons by increasing the release of and blocking the reuptake of these neurotransmitters.

Answer 46

Amphetamines

Question 47

If the neuron releases peptides, it is classified as ____.

Answer 47

peptidergic

Question 48

Where are peptide neurotransmitters made?

Answer 48

in the cell body of the neuron in the ER and Golgi

Question 49

As the action potential spreads down the T-tubule, into the muscle near the sarcoplasmic reticulum, what two components must bind in order to release calcium into the muscle?

Answer 49

DHPR and RyR1

Question 50

____ and ____ are voltage-gated Na+ channel blockers.

Answer 50

Lidocaine; Tetrodotoxin

Question 51

In a neuron, what might happen if the receptor and cell become stimulated over and over and over again?

Answer 51

the cell might: - place more receptors in the post-synaptic neuron - phosphorylate (sensitize) proteins to increase the response - increase more neurotransmitter from pre-synaptic neuron

Question 52

_____ neurons are sensory neurons that carry messages to the CNS.

Answer 52

Afferent

Question 53

What is the difference between an EPSP and an EPP?

Answer 53

EPP occurs in muscle and is ALWAYS able to cause an action potential; EPSPs may not always confer a response (axon hillock will determine that)

Question 54

When ____ is available, actin and myosin can interact with each other and cause muscle contraction.

Answer 54

calcium

Question 55

After a muscle contraction, how is calcium removed?

Answer 55

1. SERCA back into sarcoplasmic reticulum | 2. ATPase pump out of the cell

Question 56

_____ is a storage mechanism for calcium, located in the sarcoplasmic reticulum, that binds calcium to allow the uptake of more.

Answer 56

Calsequestrin

Question 57

____ is an autoimmune disease where the body produces antibodies against the acetylcholine nicotinic receptors causing weakening of skeletal muscle.

Answer 57

Myasthenia gravis

Question 58

What do peptide neurotransmitters require for synthesis?

Answer 58

cell machinery - ER and Golgi

Question 59

Are the actions of physostigmine permanent?

Answer 59

NO

Question 60

If the neuron releases acetylcholine, it is classified as ____.

Answer 60

cholinergic

Question 61

Why do cocaine users "feel good" and are able to avoid sleeping for many hours?

Answer 61

because cocaine blocks the reuptake of dopamine (mood) and norepinephrine (wakefulness)

Question 62

What happens when the skeletal muscle becomes very disorganized, such as in patients with with a mutation in their dystrophin proteins?

Answer 62

contraction strength of muscle severely decreases

Question 63

SSRI's inhibit the reuptake of ____ in the synaptic cleft, maintaining the levels available in the brain.

Answer 63

5-HT (serotonin)

Question 64

What element is critical for muscle contraction?

Answer 64

calcium

Question 65

The binding of acetylcholine to the nicotinic receptors allows which ion to depolarize the cell?

Answer 65

Na+ (and some outflow of K+, too)

Question 66

What agent blocks the acetylcholine receptor channel and prevents muscle contraction?

Answer 66

Tubocurarine

Question 67

Can the body put more receptors for a certain molecule into the synapse?

Answer 67

YES - if the cell becomes excited over and over again

Question 68

What must happen for DHPR receptors to bind to RyR1 and release calcium into the muscle?

Answer 68

they must change conformation after reacting to depolarization

Question 69

You are a dentist and inject your patient with lidocaine. You are blocking their pain by inhibiting what from happening?

Answer 69

the action potential of the voltage-gated Na+ channels

Question 70

If the neuron releases noradrenaline, it is classified as ____.

Answer 70

noradrenergic

Question 71

Where does long term potentiation primarily occur in the brain?

Answer 71

hippocampus