Question 1

In a resting neuron:

Accepted Answer

A)  the concentration of potassium ions is about 10 times greater inside the cell than in the extracellular fluid. 
B)  excitatory postsynaptic potentials hyperpolarize the membrane. 
C)  voltage-activated sodium channels are pumping sodium inside the cell against its concentration gradient. 
D)  the membrane is more permeable to sodium than potassium ions. 
E)  inhibitory postsynaptic potentials depolarize the membrane. 
A)  the concentration of potassium ions is about 10 times greater inside the cell than in the extracellular fluid. 
B)  excitatory postsynaptic potentials hyperpolarize the membrane. 
C)  voltage-activated sodium channels are pumping sodium inside the cell against its concentration gradient. 
D)  the membrane is more permeable to sodium than potassium ions. 
E)  inhibitory postsynaptic potentials depolarize the membrane.

Question 2

Figure 41-3   Refer to the accompanying figure. Depolarization 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 3

Dr. Askins performs an electrophysiology experiment. She records a neuron firing an action potential. What voltage does she record during each action potential spike?

Accepted Answer

A)  -70 mV 
B)  -55 mV 
C)  +35 mV 
D)  +55 mV 
E)  +70 mV 
A)  -70 mV 
B)  -55 mV 
C)  +35 mV 
D)  +55 mV 
E)  +70 mV

Question 4

Figure 41-1   Refer to the accompanying figure. Which structure integrates incoming signals?

Accepted Answer

A)  2 
B)  4 
C)  5 
D)  6 
E)  8 
A)  2 
B)  4 
C)  5 
D)  6 
E)  8

Question 5

Match between columns
                        Premises: A Schwann cell may form this.
An oligodendrocyte may form this.
This receives stimuli from another cell.
Voltage-gated NaS1U1P1+S1S1P0 channels are clustered here.
Neurotransmitters are typically released from here.
This may be more than one meter long.
Neurotransmitters are stored here.
This transports neural impulses away from the cell body.

Accepted Answer

The Answer of dendrite and synaptic vesicle and node of is...

Question 6

What event triggers the release of neurotransmitters?

Accepted Answer

A)  Calcium induces the fusion of synaptic vesicles with the presynaptic membrane. 
B)  Sodium induces the fusion of synaptic vesicles with the presynaptic membrane. 
C)  Potassium induces the fusion of synaptic vesicles with the presynaptic membrane. 
D)  Calcium activates enzymes that degrade synaptic vesicles. 
E)  Sodium activates enzymes that degrade synaptic vesicles. 
A)  Calcium induces the fusion of synaptic vesicles with the presynaptic membrane. 
B)  Sodium induces the fusion of synaptic vesicles with the presynaptic membrane. 
C)  Potassium induces the fusion of synaptic vesicles with the presynaptic membrane. 
D)  Calcium activates enzymes that degrade synaptic vesicles. 
E)  Sodium activates enzymes that degrade synaptic vesicles.

Question 7

In convergence , a single neuron is controlled by signals from two or more presynaptic neurons. 
____________________

Accepted Answer

A) True 
 B)False

Question 8

Since all action potentials are identical, the intensity of a sensation depends on:

Accepted Answer

A)  whether a myelinated or unmyelinated neuron has been stimulated. 
B)  the duration of the stimulation. 
C)  whether the neuron stimulated is a pre- or postsynaptic neuron. 
D)  the total number of neurons stimulated and the frequency of their discharge. 
E)  the presence of an EPSP or IPSP, which allows for a graded response. 
A)  whether a myelinated or unmyelinated neuron has been stimulated. 
B)  the duration of the stimulation. 
C)  whether the neuron stimulated is a pre- or postsynaptic neuron. 
D)  the total number of neurons stimulated and the frequency of their discharge. 
E)  the presence of an EPSP or IPSP, which allows for a graded response.

Question 9

Which molecule acts as a retrograde messenger at many synapses?

Accepted Answer

A)  GABA 
B)  glycine 
C)  serotonin 
D)  substance P 
E)  nitric oxide 
A)  GABA 
B)  glycine 
C)  serotonin 
D)  substance P 
E)  nitric oxide

Question 10

Acetylcholine is a neurotransmitter released from motor neurons. 
____________________

Accepted Answer

A) True 
 B)False

Question 11

Figure 41-2   The accompanying figure represents a sequence of events occurring in the neuronal membrane (designated by the numbers 1 and 2). The letter "I" indicates an ion. What event is mostly likely being portrayed in this figure?

Accepted Answer

A)  activation of voltage-gated sodium channels 
B)  activation of voltage-gated potassium channels 
C)  activation of voltage-gated chloride channels 
D)  activation of sodium-chloride pumps 
E)  activation of sodium-potassium pumps 
A)  activation of voltage-gated sodium channels 
B)  activation of voltage-gated potassium channels 
C)  activation of voltage-gated chloride channels 
D)  activation of sodium-chloride pumps 
E)  activation of sodium-potassium pumps

Question 12

Figure 41-3   In the accompanying figure, label A represents:

Accepted Answer

A)  resting state. 
B)  repolarization 
C)  threshold level. 
D)  equilibrium potential. 
E)  hyperpolarization. 
A)  resting state. 
B)  repolarization 
C)  threshold level. 
D)  equilibrium potential. 
E)  hyperpolarization.

Question 13

In a neuron at rest, there is a(n) higher concentration of sodium ions outside the cell than inside. 
____________________

Accepted Answer

A) True 
 B)False

Question 14

The sodium-potassium pump transports two Na+ out of the cell for every two K+ transported in. 
____________________

Accepted Answer

A) True 
 B)False

Question 15

What happens when the membrane potential of a neuron reaches the threshold level?

Accepted Answer

A)  Voltage-gated sodium channels open, and sodium diffuses out of the cell. 
B)  Voltage-gated potassium channels open for a very brief period. 
C)  Voltage-gated sodium channels close, so sodium cannot diffuse out of the cell. 
D)  The sodium channel protein changes its shape to open the gates of the channel. 
E)  The membrane potential is more negative than when at rest. 
A)  Voltage-gated sodium channels open, and sodium diffuses out of the cell. 
B)  Voltage-gated potassium channels open for a very brief period. 
C)  Voltage-gated sodium channels close, so sodium cannot diffuse out of the cell. 
D)  The sodium channel protein changes its shape to open the gates of the channel. 
E)  The membrane potential is more negative than when at rest.

Question 16

In divergence, one neuron:

Accepted Answer

A)  is controlled by several neurons. 
B)  is controlled by several neurotransmitter substances. 
C)  contains several different types of ion channels. 
D)  controls several other neurons. 
E)  contains several different types of receptors. 
A)  is controlled by several neurons. 
B)  is controlled by several neurotransmitter substances. 
C)  contains several different types of ion channels. 
D)  controls several other neurons. 
E)  contains several different types of receptors.

Question 17

Figure 41-3   Step 2 in the accompanying figure is accomplished by an influx of:

Accepted Answer

A)  Ca2+ 
B)  Na2+ 
C)  K+ 
D)  Na 
E)  K 
A)  Ca2+ 
B)  Na2+ 
C)  K+ 
D)  Na 
E)  K

Question 18

What did Alan Hodgkin and Andrew Huxley conclude from their squid axon experiments?

Accepted Answer

A)  The passage of Na+ ions into a neuron and K+ ions out of a neuron results in an action potential. 
B)  The passage of K+ ions into a neuron and Na+ ions out of a neuron results in an action potential. 
C)  The passage of K+ ions into a neuron and Ca+ ions out of a neuron results in an action potential. 
D)  The passage of Cl- ions into a neuron and K+ ions out of a neuron results in an action potential. 
E)  The passage of Cl- ions into a neuron and Ca+ ions out of a neuron results in an action potential. 
A)  The passage of Na+ ions into a neuron and K+ ions out of a neuron results in an action potential. 
B)  The passage of K+ ions into a neuron and Na+ ions out of a neuron results in an action potential. 
C)  The passage of K+ ions into a neuron and Ca+ ions out of a neuron results in an action potential. 
D)  The passage of Cl- ions into a neuron and K+ ions out of a neuron results in an action potential. 
E)  The passage of Cl- ions into a neuron and Ca+ ions out of a neuron results in an action potential.

Question 19

Saltatory conduction:

Accepted Answer

A)  does not involve voltage-activated potassium ion channels. 
B)  can occur in both myelinated and unmyelinated neurons. 
C)  is slightly slower than continuous conduction. 
D)  is more energy efficient than continuous conduction. 
E)  allows nerve impulses to jump from Schwann cell to Schwann cell. 
A)  does not involve voltage-activated potassium ion channels. 
B)  can occur in both myelinated and unmyelinated neurons. 
C)  is slightly slower than continuous conduction. 
D)  is more energy efficient than continuous conduction. 
E)  allows nerve impulses to jump from Schwann cell to Schwann cell.

Question 20

In Alzheimer's disease , neurons that secrete which neurotransmitter are particularly affected?

Accepted Answer

A)  epinephrine 
B)  dopamine 
C)  serotonin 
D)  acetylcholine 
E)  GABA 
A)  epinephrine 
B)  dopamine 
C)  serotonin 
D)  acetylcholine 
E)  GABA

Exam 41: Neural Signaling

In a resting neuron:

Figure 41-3 Refer to the accompanying figure. Depolarization is indicated by the label:

Dr. Askins performs an electrophysiology experiment. She records a neuron firing an action potential. What voltage does she record during each action potential spike?

Figure 41-1 Refer to the accompanying figure. Which structure integrates incoming signals?

What event triggers the release of neurotransmitters?

In convergence , a single neuron is controlled by signals from two or more presynaptic neurons. ____________________

Since all action potentials are identical, the intensity of a sensation depends on:

Which molecule acts as a retrograde messenger at many synapses?

Acetylcholine is a neurotransmitter released from motor neurons. ____________________

Figure 41-2 The accompanying figure represents a sequence of events occurring in the neuronal membrane (designated by the numbers 1 and 2). The letter "I" indicates an ion. What event is mostly likely being portrayed in this figure?

Figure 41-3 In the accompanying figure, label A represents:

In a neuron at rest, there is a(n) higher concentration of sodium ions outside the cell than inside. ____________________

The sodium-potassium pump transports two Na+ out of the cell for every two K+ transported in. ____________________

What happens when the membrane potential of a neuron reaches the threshold level?

In divergence, one neuron:

Figure 41-3 Step 2 in the accompanying figure is accomplished by an influx of:

What did Alan Hodgkin and Andrew Huxley conclude from their squid axon experiments?

Saltatory conduction:

In Alzheimer's disease , neurons that secrete which neurotransmitter are particularly affected?

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Introduction to Darwinian Evolution

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The sodium-potassium pump transports two Na⁺ out of the cell for every two K⁺ transported in. ____________________