Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SS103 - Physiology > Chapter 7: Nerve Cells & Electrical Signalling > Flashcards

Chapter 7: Nerve Cells & Electrical Signalling Flashcards

1
Q

Which of the following correctly lists the components of the central nervous system?

A

brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which of the following is located in the autonomic nervous system?

A

both sympathetic and parasympathetic nervous systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which of the following accurately describes afferent neurons?

A

They transmit information from the periphery to the CNS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the functional unit of the nervous system?

A

neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

On what portion of the neuron do action potentials propagate?

A

axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Information is transmitted from cell to cell across the chemical synapse via a(n) ________.

A

neurotransmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

An action potential originates at the ________ and travels along the axon until it reaches the ________.

A

axon hillock : axon terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of ion channels in the membrane of neurons allow ions to move across the membrane at rest and thereby contribute to resting membrane potential?

A

leak channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of ion channels in the membrane of neurons open or close in response to a neurotransmitter binding to its receptor?

A

ligand-gated channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In a neuron, where is the greatest concentration of voltage-gated sodium and voltage-gated potassium channels?

A

axon hillock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In a neuron, where are voltage-gated calcium channels located?

A

axon terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the structural classification of a neuron composed of a single axon and a number of dendritic projections from the nerve cell body?

A

multipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which of the following is a functional classification of neurons that, for the most part, are bipolar in structure and carry information from the peripheral axon to the central axon?

A

afferent neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which of the following terms is NOT used to describe a bundle of axons in the central or peripheral nervous system?

A

ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which of the following cells is NOT classified as a glial cell?

A

ventricular cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of cell enhances the velocity of electrical transmission of an action potential along an axon in the central nervous system?

A

oligodendrocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which of the following best describes the function of the myelin sheath?

A

reduce a membraneʹs ion permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which of the following is the correct term for the movement of an electrical charge across a membrane?

A

current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following determines the resistance to an ionʹs movement across a membrane?

A

ion channels within the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the inverse of resistance?

A

conductance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which of the following is NOT a factor involved in the determination of resting membrane potential?

A

concentration of sodium receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which of the following statements about sodium is FALSE?

A

At the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which of the following best describes the electrochemical forces acting on sodium and potassium ions at the resting membrane potential?

A

The force on sodium ions is to move into the cell, and the force on potassium ions is to move out of the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Given a cation with an equilibrium potential of -55 mV, if the plasma membrane of the cell is permeable only to this ion, then which of the following best describes the resting membrane potential?

A

-55 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

At the resting membrane potential, the membrane is most permeable to ________, which moves ________ the cell due to its electrochemical gradient.

A

potassium : out of

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

At the resting membrane potential, the electrochemical gradient for sodium across the membrane is such that the net flux for sodium movement is directed ________, thereby causing the cellʹs membrane potential to become more ________.

A

inward : positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The membrane potential at which there is no net flux of an ion across the membrane is called that ionʹs ________.

A

equilibrium potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The presence of the ________ prevents the dissipation of the concentration gradient for Na +.

A

Na+/K+ pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The Na+/K+ pump is called an electrogenic pump because the imbalance between ________.

A

Na+ out to K+ in leaves the inside of the cell with a net negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why is the electrical potential of a membrane at rest closest to potassiumʹs equilibrium potential than to sodiumʹs equilibrium potential?

A

more potassium channels are open, allowing more potassium to move out of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

If, under resting conditions, the membrane is much more permeable to sodium than potassium, what would happen to the resting membrane potential?

A

approach sodiumʹs equilibrium potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

As a membraneʹs permeability to a particular ion increases, membrane potential will move ________ that ionʹs ________.

A

closer to : equilibrium potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What equation is used to calculate the membrane potential based on ion concentration gradients and permeabilities?

A

GHK equation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Membrane permeability is altered in the short term (milliseconds to seconds) by changes in the ________ of ion channels.

A

gating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

The opening of an ion channel increases a cell membraneʹs ________, whereas ________ will decrease.

A

conductance : resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

The fact that a cell has an electrical potential difference across its membrane makes that cell ________.

A

polarized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

A change in a cellʹs membrane potential, such that it becomes more positive, is referred to as a ________.

A

depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

A change in a cellʹs membrane potential, such that it becomes more negative, is referred to as a ________.

A

hyperpolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

A ________ is a subthreshold change in membrane potential within the cell body that decays as it travels away from its point of origin.

A

graded potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

The direction of change in membrane potential, in response to a stimulus that initiates a graded potential, is dependent upon ________.

A

the ion channels that are opened or closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which of the following does NOT produce graded potentials?

A

arrival of a suprathreshold stimulus at the axon hillock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Which of the following statements is FALSE? (graded potentials)

A

Graded potentials and action potentials are all-or-none.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

The ________ in graded potential that occurs as current spreads along the membrane happens as a consequence of the ________ of current across the membrane.

A

decrement : leakage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Which of the following is an example of spatial summation?

A

Two stimuli from two sources produce graded potentials on the same neuron at the same
time such that the two potentials sum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Which of the following changes in membrane potential is considered excitatory?

A

depolarization only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

The spread of voltage by passive charge movement is called ________.

A

electrotonic conduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

If the graded potential remains above threshold once it reaches the ________, an action potential will be generated.

A

axon hillock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Which of the following characteristics does NOT describe an action potential?

A

rapid increase in potassium permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

The opening of sodium channels causes a rapid ________ of sodium that ________ the neuronʹs membrane.

A

influx : depolarizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

The depolarization phase of the action potential is generated by a rapid ________.

A

opening of sodium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

The repolarization phase of the action potential in a neuron is driven by the ________.

A

closure of sodium channels and opening of potassium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

The patterns of change in ion channel permeability that occur during an action potential are due to ________ gating of voltage-sensitive potassium and sodium channels.

A

time-dependent

53
Q

For the sodium channel to open and allow sodium into the cell, ________.

A

the activation and inactivation gates must both be open

54
Q

Which of the structures below lacks voltage-gated ion channels responsible for the production of action potentials?

A

epithelial cell membrane

55
Q

Which of the following events is fastest?

A

opening sodium activation gates

56
Q

Stimuli A and B are both suprathreshold stimuli that last for one second, but stimulus A is stronger. Which of the following statements is TRUE?

A

Stimulus A will cause a higher frequency of action potentials.

57
Q

The repolarization phase of action potentials in neurons is due primarily to ________.

A

potassium flow out of the cell

58
Q

During which of the following states are the majority of voltage-gated sodium channels closed and incapable of opening?

A

during the absolute refractory period

59
Q

The regenerative nature of a sodium channelʹs activation gate refers to the situation where an activation gate opens causing a depolarization that triggers which of the following?

A

opening of other sodium channelsʹ activation gates

60
Q

The stimulation of an inadequate number of sodium channels for the generation of a positive sodium channel feedback loop is considered a ________ stimulus.

A

subthreshold

61
Q

In order to generate an action potential, the magnitude of the inward sodium current must be large enough to overcome which of the following?

A

outward potassium current

62
Q

What terminates the positive feedback loop that is involved in the generation of an action potential?

A

closure of inactivation gates on sodium channels

63
Q

Why will the magnitude of an action potential never reach sodiumʹs equilibrium potential?

A

the inward movement of sodium is countered by the outward movement of potassium

64
Q

The all-or-none principle, associated with the action potential, states that ________.

A

once membrane potential reaches threshold, an action potential will be generated and
that action potential will always be the same magnitude

65
Q

In order for a neuron to move from the absolute to the relative refractory period, a majority of that neuronʹs sodium channels must have their ________.

A

inactivation gates open

66
Q

Toward the end of the relative refractory period, the continued decrease in stimulus intensity required to initiate an action potential is caused by ________.

A

decreased potassium permeability

67
Q

The stimulus intensity required to initiate an action potential is ________ through the course of the relative refractory period.

A

progressively reduced

68
Q

Which of the following characteristics of an action potential does NOT result directly from the refractory period?

A

the peak level of depolarization reached

69
Q

The time between action potentials is directly determined by the ________ the graded potential at the axon hillock.

A

amplitude of

70
Q

For an unmyelinated axon, conduction velocity is primarily determined by the ________.

A

diameter of the axon

71
Q

As an action potential is propagated away from the axon hillock, why does propagation continue in one direction?

A

the region just behind the action potential is in the absolute refractory period

72
Q

In myelinated nerve fibers, where do action potentials occur?

A

nodes of Ranvier

73
Q

The jumping of an action potential from node-to-node is called ________.

A

saltatory conduction

74
Q

Which of the following axons would have the fastest conduction velocity?

A

diameter = 20 microns, myelinated

75
Q

What percentage of people with diabetes develop peripheral neuropathy?

A

30

76
Q

What percentage of people with neuropathy have it secondary to diabetes?

A

30

77
Q

Why do the distributions of sodium and potassium ions across the plasma membrane of neurons not change appreciably, even following hundreds of action potentials?

A

The movement of sodium and potassium ions that occurs during an action potential is
countered by the active transport of these ions by the Na+/K+ pump.

78
Q

Effector organs act as receptors that detect information about the external environment and transmit that information to the central nervous system.

A

FALSE

79
Q

Excitable cells are capable of producing action potentials.

A

TRUE

80
Q

Axons can branch.

A

TRUE

81
Q

Leak channels are most concentrated in the soma of neurons.

A

FALSE

82
Q

Afferent neurons are generally bipolar neurons.

A

TRUE

83
Q

Oligodendrocytes are located in the peripheral nervous system, providing the myelin sheath that forms the nodes of Ranvier.

A

FALSE

84
Q

Schwann cells are the only glial cells in the peripheral nervous system.

A

TRUE

85
Q

The number of ions whose movement across the membrane creates the resting membrane potential are so few that their movement does not affect that ionʹs concentration gradient.

A

TRUE

86
Q

The membrane potential of a cell is determined exclusively by that cellʹs sodium and potassium permeability.

A

FALSE

87
Q

At the resting membrane potential, a cell is at equilibrium.

A

FALSE

88
Q

The Na+/K+ pump is electrogenic.

A

TRUE

89
Q

An ionʹs net electrochemical force will tend to move that ion across the membrane in a direction that will cause membrane potential to move toward that ionʹs equilibrium potential.

A

TRUE

90
Q

The Nernst equation is used to calculate the resting membrane potential.

A

FALSE

91
Q

The GHK equation is used to calculate the equilibrium potential for a specific ion.

A

FALSE

92
Q

In temporal summation, stimuli from different sources are applied at the same time such that they overlap and sum.

A

FALSE

93
Q

Excitatory graded potentials are those where the stimulus initiates a hyperpolarization of the cell.

A

FALSE

94
Q

Under resting conditions, the sodium channel responsible for generating an action potential is closed and incapable of opening.

A

FALSE

95
Q

Both activation and inactivation gates of a sodium channel are stimulated at the same time by a depolarization with the inactivation gate acting more slowly than the activation gate, thereby allowing sodium to enter the cell.

A

TRUE

96
Q

The magnitude of the action potential is dependent upon the extent to which the change in membrane potential is above threshold.

A

FALSE

97
Q

During the relative refractory period, the stimulus intensity required to initiate an action potential is elevated.

A

TRUE

98
Q

Once an action potential is generated, it will always depolarize the neighboring membrane above threshold, ensuring the action potential will travel along the axon without interruption.

A

TRUE

99
Q

Tingling can be a sign of diabetic neuropathy.

A

TRUE

100
Q

Diabetic neuropathy can affect nerves of the autonomic nervous system.

A

TRUE

101
Q

autonomic nervous system

A

The portion of the efferent branch of the nervous system that communicates to glands and cardiac muscle.

102
Q

efferent nervous system

A

The portion of the peripheral nervous system that communicates to effector organs.

103
Q

somatic nervous system

A

Portion of the efferent nervous system that communicates with skeletal muscle.

104
Q

afferent nervous system

A

The portion of the peripheral nervous system that transmits information from sensory receptors to the central nervous system.

105
Q

central nervous system

A

The brain and spinal cord.

106
Q

peripheral nervous system

A

Provides communication between peripheral organs and the brain and spinal cord.

107
Q

enteric nervous system

A

Nervous system of the intestinal tract.

108
Q

Information gathered about our internal environment (i.e., fullness of the stomach, blood pressure, etc.) is called ________ information.

A

visceral

109
Q

What is the most common neuronal cell type?

A

interneuron

110
Q

What is the only glial cell found outside of the central nervous system?

A

Schwann cell

111
Q

Each ________ provides the myelin sheath for many axons in the central nervous system.

A

oligodendrocyte

112
Q

Once a membrane potential has been developed, the force that drives a particular ion across the membrane is its ________.

A

electrochemical gradient

113
Q

When they are not at equilbrium, an ion will move across the membrane in a direction that moves membrane potential toward that ionʹs ________.

A

equilibrium potential

114
Q

What is the passive spread of current along a membrane called?

A

electrotonic conduction

115
Q

Following the opening of the activation gate of the sodium channel, the ________ gate closes shortly thereafter.

A

inactivation

116
Q

The inactivation gate is opened by ________

A

repolarization of the membrane to resting membrane potential

117
Q

The fact that the opening of some sodium channels can induce several other sodium channels to open describes the ________ property of these channels.

A

regenerative

118
Q

What is the level of membrane depolarization required to induce the sodium channelʹs positive feedback loop called?

A

threshold

119
Q

The type of ion channels located along the axon is (ligand-gated channels / voltage-gated channels).

A

voltage-gated channels

120
Q

In the peripheral nervous system, myelin is formed by ________. In the central nervous system, myelin is formed by ________. Gaps in the myelin are called ________. Propagation of action potentials in myelinated axons is called ________.

A

Schwann cells : oligodendrocytes : nodes of Ranvier : saltatory conduction

121
Q

At rest, the plasma membrane is more permeable to (sodium / potassium).

A

potassium

122
Q

The resting membrane potential is close to the (sodium / potassium) equilibrium potential.

A

potassium

123
Q

Which is larger, an action potential or a graded potential? Which lasts longer, an action potential or a graded potential?

A

action potential : graded potential

124
Q

During the rapid depolarization phase of an action potential, the plasma membrane is more permeable to (sodium / potassium).

A

sodium

125
Q

The sodium inactivation gate (opens / closes) with depolarization.

A

closes

126
Q

Increased permeability to what ion is responsible for the relative refractory period?

A

potassium

127
Q

As the membrane potential moves further away from the equilibrium potential for a certain ion, the electrochemical force acting on that ion (increases / decreases).

A

increases

128
Q

At the peak of an action potential, the electrochemical force is greater for (sodium / potassium).

A

potassium

129
Q

The current produced by a specific ion moving across the plasma membrane increases as conductance (increases / decreases).

A

increases

SS103 - Physiology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions