Question 1

The botulinum toxin reduces the synaptic release of

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. A

Question 2

The point of connection between two communicating neurons is called the

Accepted Answer

A)  axon hillock. 
B)  dendrite. 
C)  synapse. 
D)  cell body. 
E)  glia. 
A)  axon hillock. 
B)  dendrite. 
C)  synapse. 
D)  cell body. 
E)  glia. C

Question 3

What happens when a resting neuron's membrane depolarizes?

Accepted Answer

A)  There is a net diffusion of Na+ out of the cell. 
B)  The equilibrium potential for K+ (EK) becomes more positive. 
C)  The neuron's membrane voltage becomes more positive. 
D)  The neuron is less likely to generate an action potential. 
E)  The cell's inside is more negative than the outside. 
A)  There is a net diffusion of Na+ out of the cell. 
B)  The equilibrium potential for K+ (EK) becomes more positive. 
C)  The neuron's membrane voltage becomes more positive. 
D)  The neuron is less likely to generate an action potential. 
E)  The cell's inside is more negative than the outside. C

Question 4

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

Accepted Answer

A)  the threshold value in the postsynaptic membrane is different for cell X and cell Y. 
B)  cell Y forms chemical synapses, whereas cell X forms electrical synapses. 
C)  the axon of cell X is myelinated, but that of cell Y is not. 
D)  only cell Y produces an enzyme that terminates the activity of the neurotransmitter. 
E)  cells X and Y express different receptor molecules for this particular neurotransmitter. 
A)  the threshold value in the postsynaptic membrane is different for cell X and cell Y. 
B)  cell Y forms chemical synapses, whereas cell X forms electrical synapses. 
C)  the axon of cell X is myelinated, but that of cell Y is not. 
D)  only cell Y produces an enzyme that terminates the activity of the neurotransmitter. 
E)  cells X and Y express different receptor molecules for this particular neurotransmitter.

Question 5

For the following questions, refer to the graph of an action potential in Figure 37.1.
   Figure 37.1
-The neuronal membrane is at its resting potential at label

Accepted Answer

A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E. 
A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E.

Question 6

A chemical that affects neuronal function but is not stored in presynaptic vesicles is

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA.

Question 7

The fastest possible conduction velocity of action potentials is observed in

Accepted Answer

A)  thin, nonmyelinated neurons. 
B)  thin, myelinated neurons. 
C)  thick, nonmyelinated neurons. 
D)  thick, myelinated neurons. 
A)  thin, nonmyelinated neurons. 
B)  thin, myelinated neurons. 
C)  thick, nonmyelinated neurons. 
D)  thick, myelinated neurons.

Question 8

A simple nervous system

Accepted Answer

A)  must include chemical senses, mechanoreception, and vision. 
B)  includes a minimum of 12 effector neurons. 
C)  has information flow in only one direction: toward an integrating center. 
D)  has information flow in only one direction: away from an integrating center. 
E)  includes sensory information, an integrating center, and effectors. 
A)  must include chemical senses, mechanoreception, and vision. 
B)  includes a minimum of 12 effector neurons. 
C)  has information flow in only one direction: toward an integrating center. 
D)  has information flow in only one direction: away from an integrating center. 
E)  includes sensory information, an integrating center, and effectors.

Question 9

Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

Accepted Answer

A)  fully permeable to sodium ions. 
B)  slightly permeable to sodium ions. 
C)  fully permeable to calcium ions. 
D)  impermeable to sodium ions. 
E)  highly permeable to chloride ions. 
A)  fully permeable to sodium ions. 
B)  slightly permeable to sodium ions. 
C)  fully permeable to calcium ions. 
D)  impermeable to sodium ions. 
E)  highly permeable to chloride ions.

Question 10

An action potential can start in the middle of an axon and proceed in both opposite directions when

Accepted Answer

A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold. 
A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold.

Question 11

The nucleus and most of the organelles in a neuron are located in the

Accepted Answer

A)  dendritic region. 
B)  axon hillock. 
C)  axon. 
D)  cell body. 
E)  axon terminals. 
A)  dendritic region. 
B)  axon hillock. 
C)  axon. 
D)  cell body. 
E)  axon terminals.

Question 12

The major inhibitory neurotransmitter of the human brain is

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  glutamate. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  glutamate. 
D)  nitric oxide. 
E)  GABA.

Question 13

For the following questions, refer to the graph of an action potential in Figure 37.1.
   Figure 37.1
-The minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label

Accepted Answer

A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E. 
A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  E.

Question 14

Most of the synapses in vertebrates conduct information in only one direction

Accepted Answer

A)  as a result of the nodes of Ranvier. 
B)  as a result of voltage-gated sodium channels found only in the vertebrate system. 
C)  because vertebrate nerve cells have dendrites. 
D)  because only the postsynaptic cells can bind and respond to neurotransmitters. 
E)  because the sodium-potassium pump moves ions in one direction. 
A)  as a result of the nodes of Ranvier. 
B)  as a result of voltage-gated sodium channels found only in the vertebrate system. 
C)  because vertebrate nerve cells have dendrites. 
D)  because only the postsynaptic cells can bind and respond to neurotransmitters. 
E)  because the sodium-potassium pump moves ions in one direction.

Question 15

Neurotransmitters affect postsynaptic cells by

Accepted Answer

A)  initiating signal transduction pathways in the cells. 
B)  causing molecular changes in the cells. 
C)  affecting ion-channel proteins. 
D)  altering the permeability of the cells. 
E)  All of these options are correct. 
A)  initiating signal transduction pathways in the cells. 
B)  causing molecular changes in the cells. 
C)  affecting ion-channel proteins. 
D)  altering the permeability of the cells. 
E)  All of these options are correct.

Question 16

In a simple synapse, neurotransmitter chemicals are received by

Accepted Answer

A)  the dendritic membrane. 
B)  the presynaptic membrane. 
C)  axon hillocks. 
D)  cell bodies. 
E)  ducts on the smooth endoplasmic reticulum. 
A)  the dendritic membrane. 
B)  the presynaptic membrane. 
C)  axon hillocks. 
D)  cell bodies. 
E)  ducts on the smooth endoplasmic reticulum.

Question 17

The somatic nervous system can alter the activities of its targets, the skeletal muscle fibers, because

Accepted Answer

A)  it is electrically coupled by gap junctions to the muscles. 
B)  its signals bind to receptor proteins on the muscles. 
C)  its signals reach the muscles via the blood. 
D)  its light pulses activate contraction in the muscles. 
E)  it is connected to the internal neural network of the muscles. 
A)  it is electrically coupled by gap junctions to the muscles. 
B)  its signals bind to receptor proteins on the muscles. 
C)  its signals reach the muscles via the blood. 
D)  its light pulses activate contraction in the muscles. 
E)  it is connected to the internal neural network of the muscles.

Question 18

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of a

Accepted Answer

A)  voltage-gated sodium channel. 
B)  voltage-gated potassium channel. 
C)  ligand-gated sodium channel. 
D)  second-messenger-gated sodium channel. 
E)  chemical that inhibits action potentials. 
A)  voltage-gated sodium channel. 
B)  voltage-gated potassium channel. 
C)  ligand-gated sodium channel. 
D)  second-messenger-gated sodium channel. 
E)  chemical that inhibits action potentials.

Question 19

In the sequence of permeability changes for a complete action potential, the first of these events that occurs is the

Accepted Answer

A)  activation of the sodium-potassium "pump." 
B)  inhibition of the sodium-potassium "pump." 
C)  opening of voltage-gated sodium channels. 
D)  closing of voltage-gated potassium channels. 
E)  opening of voltage-gated potassium channels. 
A)  activation of the sodium-potassium "pump." 
B)  inhibition of the sodium-potassium "pump." 
C)  opening of voltage-gated sodium channels. 
D)  closing of voltage-gated potassium channels. 
E)  opening of voltage-gated potassium channels.

Question 20

The "threshold" potential of a membrane is the

Accepted Answer

A)  point of separation from a living to a dead neuron. 
B)  lowest frequency of action potentials a neuron can produce. 
C)  minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D)  minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E)  peak amount of depolarization seen in an action potential. 
A)  point of separation from a living to a dead neuron. 
B)  lowest frequency of action potentials a neuron can produce. 
C)  minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D)  minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E)  peak amount of depolarization seen in an action potential.

Exam 37: Neurons, Synapses, and Signaling

The botulinum toxin reduces the synaptic release of

The point of connection between two communicating neurons is called the

What happens when a resting neuron's membrane depolarizes?

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

For the following questions, refer to the graph of an action potential in Figure 37.1. Figure 37.1 -The neuronal membrane is at its resting potential at label

A chemical that affects neuronal function but is not stored in presynaptic vesicles is

The fastest possible conduction velocity of action potentials is observed in

A simple nervous system

Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

An action potential can start in the middle of an axon and proceed in both opposite directions when

The nucleus and most of the organelles in a neuron are located in the

The major inhibitory neurotransmitter of the human brain is

For the following questions, refer to the graph of an action potential in Figure 37.1. Figure 37.1 -The minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label

Most of the synapses in vertebrates conduct information in only one direction

Neurotransmitters affect postsynaptic cells by

In a simple synapse, neurotransmitter chemicals are received by

The somatic nervous system can alter the activities of its targets, the skeletal muscle fibers, because

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of a

In the sequence of permeability changes for a complete action potential, the first of these events that occurs is the

The "threshold" potential of a membrane is the

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