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HBM exam questions > Electrical properties of neuronal cells > Flashcards

Electrical properties of neuronal cells Flashcards

1
Q

True/false
“At presynaptic terminals action potentials can be converted into chemical signals at chemical synapses and also propagated directly as an electrical signal at electricalsynapses.”

A

True

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2
Q

True/false
“Action potentials are generated in the dendrites of neurons where they are mediated by
non-gated ion channels”

A

False

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3
Q

True/false

“There is an influx of Ca2+ via voltage-gated channels during action potentials”

A

True

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4
Q

True/false
“The conduction velocity of action potentials is affected by the diameter of the axons and
by their myelination”

A

True

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5
Q

True/false

“Action potentials are only mediated by activation of voltage-gated channels”

A

True

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6
Q

Catecholamines are important neurotransmitters linked with many different functions. How are they synthesized? Start with the precursor and end with the final product (each compound in the correct order). State also the name and role of the rate-limiting enzyme.

A

Tyrosine -> DOPA -> Dopamine -> Noradrenaline -> Adrenaline

Tyrosine hydoxylase: rate-limiting enzyme

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7
Q

How is glutamate inactivated?

A

It is (primarily) taken up into adjacent astrocytes in which it is converted to glutamine.

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8
Q

How is acetylcholine inactivated?

A

It is broken down by acetylcholinesterase into choline and acetate, choline is then taken
up in the nerve terminal.

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9
Q

True/False

“The ion channels actively transport ions across the plasma membrane”

A

False

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10
Q

True/false
“Ion channels allow ions to pass through in one direction from the outside to the inside of
a neuron”

A

False

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11
Q

True/false
“Ion channels are endowed with a selectivity filter that specifically recognize and select a
given ion type”

A

True

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12
Q

True/false

“The activation and inactivation gates are located in different parts of Na+ channels”

A

True

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13
Q

True/false

“The direction of the flux of ion is only determined by the driving force”

A

True

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14
Q

What characterizes the resting membrane potential?

A

The resting membrane potential is determined by K+ and Na+ ion flow through leak channels

Na/K-ATPase plays a supporting role and hence its activation is required for maintaining the resting membrane potential

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15
Q

True/false
“The passive membrane properties are specific to each neuron and do not involve
activation of ion channels”

A

True

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16
Q

True/false

“The spatial summation is more efficient in neurons with a long space constant”

A

True

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17
Q

True/false

“The temporal summation is also more efficient in neurons with a long space constant”

A

False

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18
Q

True/false

“Neurons with large time and space constants have less efficient summation”

A

False

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19
Q

True/false

“The shape of action potentials is not determined by the time constant of a neuron”

A

True

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20
Q

True/false

“Both gated- and non-gated channels are closed at the resting membrane potential”

A

False

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21
Q

True/false

“Gated channels become open only in response to specific stimuli”

A

True

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22
Q

True/false

“Non-gated ion channels are not present in all neurons”

A

False

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23
Q

True/false

“Ligand-gated channels can be gated by stimuli from the outside or the inside of a neuron”

A

True

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24
Q

True/false

“Both gated and non-gated ion channels become inactivated with a prolonged stimulation”

A

False

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25
Q

True/false
“The permeability of Na and K ions through non-gated channels is the same at the resting
membrane potential”

A

False

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26
Q

True/false
“Ion flux through both gated- and non-gated ion channels determines the resting membrane
potential”

A

False

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27
Q

True/false
“The resting membrane potential is set by a combined flux of Na and K ions via non-gated
channels”

A

True

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28
Q

True/false

“The direction of ion flux through ion channels is affected by the resting membrane potential”

A

True

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29
Q

True/false

“The resting membrane potential contributes to setting the driving force through different ion channels”

A

True

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30
Q

True/false

“Action potentials are triggered by ligand-gated sodium and potassium channels”

A

False

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31
Q

True/false
“The electrical signal of an action potential is converted to a chemical signal at axon
terminals via activation of voltage-gated calcium channels”

A

True

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32
Q

True/false

“Action potentials unidirectional propagation is controlled by sodium channel inactivation”

A

True

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33
Q

True/false
“The frequency of action potential firing does not change, i.e. always constant, for a given
neuron”

A

False

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34
Q

True/false

“Action potentials are only mediated by activation of voltage-gated channels”

A

True

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35
Q

True/false

“Synaptic summation is less efficient with higher time and space constants”

A

False

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36
Q

True/false
“The time and space constants do not affect the amplitude and conduction velocity of action
potentials”

A

True

37
Q

True/false

“The time and space constants affect the release of transmitters from axon terminals”

A

False

38
Q

True/false

“The time and space constants can only influence subthreshold postsynaptic potentials”

A

True

39
Q

True/false

“The resting membrane potential of a neuron determines its time and space constants”

A

False

40
Q

What is the role of afterhyperpolarization in the action potential?

A

The early afterhyperpolarization regulates the frequency of action potentials

41
Q

What is synaptic summation dependent on?

A

A) Synaptic summation depends on the time constant

B) Synaptic summation depends on the space constant

42
Q

What is the relative refractory period dependent on?

A

The relative refractory period depends on K+ channels

43
Q

What is true about cell excitability?

A

Excitability depends on voltage-gated ion channels

44
Q

True/false

“The amplitude of action potentials is determined by the neuron’s time and space constants”

A

False

45
Q

True/false

“Synaptic summation is more efficient with higher time and space constants”

A

True

46
Q

True/false
“The time and space constants affect the action potential propagation and release of
transmitters from axon terminals”

A

False

47
Q

True/false

“The time and space constants only influence sub-threshold postsynaptic potentials”

A

True

48
Q

True/false

“The time and space constants are larger at more hyperpolarized membrane potentials”

A

False

49
Q

True/false
“The electrical signal of an AP is converted to a chemical signal at synapses with only
electrical transmission via gap junctions”

A

False

50
Q

True/false

“During an action potential, all voltage-gated channels can be activated”

A

True

51
Q

True/false

“Action potentials unidirectional propagation is controlled by sodium channel inactivation”

A

True

52
Q

True/false

“The afterhyperpolarization is mediated by both voltage- and ligand-gated K+ channels”

A

True

53
Q

True/false

“The frequency of action potential firing is always constant for each neuron”

A

False

54
Q

True/false

“The driving force of ions helps to set the RMP”

A

True

55
Q

True/false

“The difference in permeability of ions is important in setting the RMP”

A

True

56
Q

True/false

“The permeability of Na vs K does not play an important role in setting the RMP”

A

False

57
Q

True/false

“The RMP does not influence the direction of ion flux through ion channels”

A

False

58
Q

True/false

“The RMP is the same for all neurons in the brain”

A

False

59
Q

True/false

“Na+ channel inactivation determines the shape, but not the propagation of action potentials”

A

False

60
Q

True/false

“The fast activation of Na+ channels and their inactivation are essential for the generation of action potentials”

A

True

61
Q

True/false

“All ion channels undergo inactivation”

A

False

62
Q

True/false

“All voltage-gated channels present in a neuron can be activated by an action potential”

A

True

63
Q

True/false

“Both voltage- and ligand-gated K+ channels underlie the afterhyperpolarizations”

A

True

64
Q

True/False

“Neurons’ time and space constants are determined by voltage-gated ion channels”

A

False

65
Q

True/False
“The time and space constants play a key role only at subthreshold membrane potentials,
that is when neurons are not firing action potentials”

A

True

66
Q

True/False
“EPSPs with large amplitudes will always summate efficiently to produce an action
potential regardless of how short the time and space constants are”

A

False

67
Q

True/False

“Small EPSPs can summate more efficiently if they occur in neurons with long space and time constants”

A

True

68
Q

True/False

“The time and space constants determine the shape and the propagation of action potentials”

A

False

69
Q

True/False

“The structure of ion channels determines the direction of the flow of ions”

A

False

70
Q

True/False
“ The opening and inactivation of an ion channel are mediated by conformational changes
occurring at different parts of a channel”

A

True

71
Q

True/False
“The direction of the flow of ions is determined by the driving force, which is independent
of the channel itself”

A

True

72
Q

True/False

“All gated channels contribute to the generation of action potentials”

A

False

73
Q

True/False

“The resting membrane potential is determined by both gated and non-gated ion channels”

A

False

74
Q

True/False

“The firing frequency of action potentials does not vary among neurons”

A

False

75
Q

True/False

“The amplitude of the slow afterhyperpolarization can affect the firing frequency of action potentials”

A

True

76
Q

True/False

“The firing frequency of neurons increases with the strength of excitatory synaptic inputs

A

True

77
Q

True/False

“Leak channels have a strong and direct influence on the firing frequency of neurons”

A

False

78
Q

True/False

“Ca2+ influx can indirectly affect the firing frequency of neurons”

A

True

79
Q

True/False

“The flow of ions through ion channels requires energy in form of ATP”

A

False

80
Q

True/False

“Ion channels allow all ions to pass through”

A

False

81
Q

True/False

“Ion channels have a selectivity filter to specifically recognize and select a given ion type”

A

True

82
Q

True/False

“Ion channels are membrane lipids that allow ion to pass only in one direction”

A

False

83
Q

True/False

“The direction of the flux of ion is only determined by the driving force”

A

True

84
Q

The resting membrane potential of neurons is around -65 mV and is determined by:

A

1: Passive flow of ions
3: Leak K+ and Na+ channels
5: Non-gated ion channels

85
Q

The passive membrane properties of neurons determine the efficacy of summation of synaptic inputs. Which of the following statement(s) is (are) correct:

1: The time and space constants do not vary between different types of neurons
2: The spatial summation increases with an increased space constant
3: The temporal summation decreases with increased space constant
4: Neurons with small time and space constants have a less efficient summation
5: The shape of action potentials is determined by the time constant of the neuron

A

2: The spatial summation increases with an increased space constant
4: Neurons with small time and space constants have a less efficient summation

86
Q

Ion channels comprise two different types: gated- and non-gated channels. Gated
ion channels display the following properties: (2 p)
1: They can only be activated by stimuli acting from the outside of neurons
2: They can be ionotropic receptors
3: They require specific stimuli to be activated
4: They contribute to setting the resting membrane potential of neurons
5: All gated ion channels become inactivated with a prolonged stimulation

A

2: They can be ionotropic receptors
3: They require specific stimuli to be activated

87
Q

An Action potential (AP) transmits the electrical signals along the axons of
neurons. Which of the following statement(s) is(are) correct: (2 p)
1: The electrical signal of an AP is converted to a chemical signal at axon
terminals
2: Action potentials are triggered by ligand-gated sodium channels
3: Action potentials unidirectional propagation is controlled by sodium channel
inactivation
4: Action potentials are mediated by voltage-gated channels
5: The amplitude of action potentials does not change with the stimulus strength

A

1: The electrical signal of an AP is converted to a chemical signal at axon
terminals
3: Action potentials unidirectional propagation is controlled by sodium channel
inactivation
4: Action potentials are mediated by voltage-gated channels

88
Q

All neurons have a resting membrane potential (RMP) around -65 mV. Which of
the following statement(s) is(are) correct: (2 p)
1: Only ion flux through gated-ion channels determines the RMP
2: The RMP is set by a combined flux of Na and K ions
3: The permeability of Na vs K does not play an important role in setting the RMP
4: The RMP influences the direction of ion flux through ion channels
5: The RMP can vary between neurons in different regions of the brain

A

2: The RMP is set by a combined flux of Na and K ions
4: The RMP influences the direction of ion flux through ion channels
5: The RMP can vary between neurons in different regions of the brain

HBM exam questions (7 decks)

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