Question 1

Multiple sclerosis is an autoimmune disease in which the body's defense system erroneously attacks the myelin sheath surrounding myelinated nerve fibers.

Accepted Answer

A) True 
 B)False

Question 2

Complete each of the following statments.
Axons can range in length from less than a millimeter to over one ____________________.

Accepted Answer

The answer of Complete each of the following statments.
Axons can...

Question 3

Graded potentials

Accepted Answer

A)   are local changes in membrane potential that occur in varying degrees of magnitude
B)   serve as short-distance signals
C)   serve as long-distance signals
D)   are local changes in membrane potential that occur in varying degrees of magnitude, and serve as short-distance signals
E)   are local changes in membrane potential that occur in varying degrees of magnitude, and serve as long-distance signalsF) C) and D)
G) A) and E)

Question 4

During the absolute refractory period, the voltage-gated Na+ channels are not capable of opening again in response to another triggering event.

Accepted Answer

A) True 
 B)False

Question 5

During the rising phase of the action potential:

Accepted Answer

A)   PK+ is much greater than PNa+.
B)   PNa+ is much greater than PK+.
C)   PK+ is the same as P Na+.
D)   Na+ efflux occurs.
E)   PNa+ is much greater than PK+, and Na+ efflux occurs.F) A) and C)
G) A) and B)

Question 6

Neuropeptides

Accepted Answer

A)   are sometimes co-secreted along with classical neurotransmitters
B)   are synthesized in the cytosol of the axon terminal
C)   act at the subsynaptic membrane of the postsynaptic neuron
D)   all of these
E)   are sometimes co-secreted along with classical neurotransmitters and are synthesized in the cytosol of the axon terminalF) A) and E)
G) D) and E)

Question 7

An action potential on a neuron develops when

Accepted Answer

A)   threshold voltage is reached on an axon
B)   voltage-gated Na+ channels open
C)   spatial and/or temporal summation of graded potentials occurs to a great enough degree
D)   the axon hillock reaches threshold
E)   all of theseF) D) and E)
G) A) and C)

Question 8

A change in a membrane potential from -70 mV to -60mV is an example of

Accepted Answer

A)   depolarization
B)   hyperpolarization
C)   polarization
D)   repolarization
E)   zero potentialF) B) and C)
G) A) and D)

Question 9

The nucleus of a neuron is housed in the

Accepted Answer

A)   axon
B)   axon hillock
C)   cell body
D)   collaterals
E)   dendritesF) A) and B)
G) A) and C)

Question 10

When chemically-gated Na+ channels open, the membrane

Accepted Answer

A)   hyperpolarizes
B)   repolarizes
C)   depolarizes
D)   becomes more negative
E)   is inhibitedF) C) and D)
G) A) and D)

Question 11

Neuron A and neuron B release a minimal amount of neurotransmitter simultaneously onto neuron C, causing neuron C to experience an action potential. This is an example of

Accepted Answer

A)   temporal summation
B)   spatial summation
C)   convergence
D)   temporal summation and convergence
E)   spatial summation and convergenceF) B) and E)
G) A) and D)

Question 12

Nerve fiber is another name for a dendrite on a neuron.

Accepted Answer

A) True 
 B)False

Question 13

Tetanus toxin

Accepted Answer

A)   combines with glycine receptors, thus blocking the action of this inhibitory neurotransmitter
B)   destroys dopamine in the region of the brain involved in controlling complex movements
C)   prevents the release of GABA onto inputs terminating on neurons that supply skeletal muscles
D)   promotes presynaptic facilitation
E)   causes retrograde flow in axonF) A) and D)
G) A) and C)

Question 14

Which of the following is responsible for the falling phase of an action potential?

Accepted Answer

A)   opening of Na+ gates
B)   Na+-K+ pump restoring the ions to their original locations
C)   greatly increased permeability to Na+
D)   ATP-ase destroying the energy supply that was maintaining the action potential at its peak
E)   none of theseF) A) and E)
G) C) and E)

Question 15

Complete each of the following statments.
Intentional, programmed cell death is called ____________________.

Accepted Answer

The answer of Complete each of the following statments.
Intentional, programmed...

Question 16

Select the incorrect statement about the action potential.

Accepted Answer

A)   It has an all-or-none characteristic.
B)   It has a refractory period.
C)   It is triggered by depolarization to threshold.
D)   It occurs along a plasma membrane.
E)   It speeds up transmission by summation.F) A) and B)
G) None of the above

Question 17

Spatial summation occurs in a postsynaptic neuron

Accepted Answer

A)   when several EPSPs from a single presynaptic input sum to reach threshold
B)   when EPSPs from several presynaptic inputs sum to reach threshold
C)   upon simultaneous interaction of an EPSP and an IPSP
D)   when several IPSPs from a single presynaptic input sum to hyperpolarize the membrane
E)   none of theseF) B) and D)
G) None of the above

Question 18

The passive current flow of a graded potential fades quickly.

Accepted Answer

A) True 
 B)False

Question 19

Select the neuropeptide.

Accepted Answer

A)   acetylcholine
B)   dopamine
C)   epinephrine
D)   cholecystokinin
E)   glycineF) B) and D)
G) A) and C)

Question 20

The grand postsynaptic potential depends on the sum of activity of the presynaptic inputs.

Accepted Answer

A) True 
 B)False

Exam 4: Principles of Neural and Hormonal Communication

When chemically-gated Na+ channels open, the membrane

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Which of the following is responsible for the falling phase of an action potential?

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The nucleus of a neuron is housed in the

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An action potential on a neuron develops when

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Select the incorrect statement about the action potential.

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The grand postsynaptic potential depends on the sum of activity of the presynaptic inputs.

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A change in a membrane potential from -70 mV to -60mV is an example of

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Neuron A and neuron B release a minimal amount of neurotransmitter simultaneously onto neuron C, causing neuron C to experience an action potential. This is an example of

Correct AnswerverifiedShow Answer

The passive current flow of a graded potential fades quickly.

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Spatial summation occurs in a postsynaptic neuron

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Graded potentials

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Multiple sclerosis is an autoimmune disease in which the body's defense system erroneously attacks the myelin sheath surrounding myelinated nerve fibers.

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Neuropeptides

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Complete each of the following statments. Intentional, programmed cell death is called ____________________.

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Select the neuropeptide.

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During the absolute refractory period, the voltage-gated Na+ channels are not capable of opening again in response to another triggering event.

Correct AnswerverifiedShow Answer

Complete each of the following statments. Axons can range in length from less than a millimeter to over one ____________________.

Correct AnswerverifiedShow Answer

Nerve fiber is another name for a dendrite on a neuron.

Correct AnswerverifiedShow Answer

Tetanus toxin

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During the rising phase of the action potential:

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When chemically-gated Na⁺ channels open, the membrane

Correct Answer
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During the absolute refractory period, the voltage-gated Na⁺ channels are not capable of opening again in response to another triggering event.

Correct Answer
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