Question 1

How can one tell if action potentials are generated by a threshold or suprathreshold stimuli?

Accepted Answer

A)   the suprathreshold will have the largest amplitude
B)   threshold stimuli will not always produce an action potential
C)   the suprathreshold stimulus will create a higher frequency of action potentials
D)   there in no difference in action potentials generated by either type of stimulus

Question 2

A major function of the nervous system is communication that allows our bodies to maintain homeostasis. In many cases reflexes will occur without our awareness. Which function of the nervous system is bypassed in this case?

Accepted Answer

A)   sensory function
B)   motor function
C)   integrative function
D)   none; all functions occur in reflexes

Question 3

An individual touches a sharp object and cries out in pain, but is unable to pull her hand away from the object. In this situation, the _________ neurons are the most likely reason she cannot respond.

Accepted Answer

A)   sensory neurons
B)   sympathetic neurons
C)   parasympathetic neurons
D)   somatic neurons

Question 4

In a dendroaxonic synapse the part of the postsynaptic cell receiving the signal is the

Accepted Answer

A)   dendrite
B)   cell body
C)   axon
D)   myelin

Question 5

You are working with some new neural cells and accidentally spill a few drops of a chemical solution into the petri dish. Shortly afterwards, you notice an increase in graded potentials in the cells. You hypothesize that the channels responsible for these graded potentials are

Accepted Answer

A)   ligand-gated
B)   leak channels
C)   mechanically-gated
D)   voltage-gated

Question 6

A surgeon is repairing damage to an individual's abdominal area, and accidentally connects a nerve that originally controlled the smooth muscle of the GI tract to the skeletal muscle of the abdominal wall. Hypothesize what might happen in this instance.

Accepted Answer

A)   The individual will no longer have voluntary control of the smooth muscle in his GI tract.
B)   The nerve will change divisions and contain only somatic neurons.
C)   Nothing, because the tissue of the GI tract responds only to the enteric nervous system, and the autonomic innervation was not vital.
D)   This area of the GI tract will no longer be able to exchange information with the CNS through this nerve.

Question 7

Summation of postsynaptic potentials determines whether or not an action potential will be generated at the axon hillock. The final amplitude of the summed potentials is dependent upon

Accepted Answer

A)   distance the post-synaptic potential has traveled
B)   the polarity of the potential (epsp or ipsp) 
C)   the timing of the potential (did they arrive close enough together to be summed) 
D)   All of the choices will affect the final amplitude.

Question 8

How does increasing the extracellular calcium concentration lead to a decrease in excitability?

Accepted Answer

A)   Ca2+ can block Na+ channels, so the extra concentration means fewer channels are available for Na+ to move through.
B)   Ca2+ increases the voltage threshold required to open the Na+ channels, so the extra concentration means channels require more stimulus.
C)   Ca2+ decreases the voltage threshold required to open the K+ channels, so the extra concentration means K+ channels will open sooner, hyperpolarizing the cell.
D)   It makes the outside of the cell more positive, so by comparison the inside is more negative and therefore less likely to depolarize.

Question 9

Anionic proteins and phosphates have little influence over the resting membrane potential (RMP)  because

Accepted Answer

A)   they are found in roughly equal concentrations across the membrane
B)   they are negatively charged, and the rmp relies on positive charges
C)   they are bound to cations and thus can't cross the membrane
D)   they do not have leak channels and thus can't cross the membrane

Question 10

Retrograde and anterograde transport occur in the

Accepted Answer

A)   axon
B)   dendrites
C)   cell body (soma) 
D)   axon hillock

Question 11

Which of the following is NOT a type of graded potential?

Accepted Answer

A)   post-synaptic potential
B)   receptor potential
C)   end plate potential
D)   resting membrane potential

Question 12

A scientist discovers that a neuron does not have adequate stores of neurotransmitter. What part of the neuron is he observing?

Accepted Answer

A)   the axon
B)   the synaptic end bulbs
C)   the dendrites
D)   the cell body

Question 13

A cell with leak channels that are only permeable to Cl- has been placed in a petri dish. Which of the following statements accurately describes the relationship between the concentration gradient and the Cl- equilibrium potential (ECl) ?

Accepted Answer

A)   A higher concentration of Cl- outside the cell will create a positive equilibrium potential.
B)   A higher concentration of Cl- inside the cell will create a positive equilibrium potential.
C)   A higher concentration of Cl- inside the cell will create a negative equilibrium potential.
D)   It does not matter what the initial concentration is because Cl- will always reach a negative equilibrium potential.

Question 14

Saltatory conduction is different from continuous conduction because it

Accepted Answer

A)   occurs in axons with myelin on them
B)   occurs in dendrites
C)   is slower than continuous conduction
D)   utilizes more energy than continuous conduction

Question 15

The doctor taps your leg just below your knee to test your reflexes. Your leg swings out at about the same time you perceive that your leg was tapped because of a

Accepted Answer

A)   diverging circuit
B)   converging circuit
C)   reverberating circuit
D)   parallel after-discharge circuit

Question 16

Speed of conduction of action potentials along an axon is increased in

Accepted Answer

A)   axons with a larger diameter
B)   axons that are myelinated
C)   axons with more axon collaterals
D)   axons with both myelin and a larger diameter

Question 17

Assume the potentials from the following combinations of dendrites reach the axon hillock/trigger zone at the same time. Which combination will have the greatest chance of generating an action potential?

Accepted Answer

A)   1, 2, 4
B)   2, 3, 4
C)   3, 4, 5
D)   1, 4, 5

Question 18

An investigator is trying to slow the rate of infection of neurons by the herpes simplex virus. Which of these proteins in the neuron could she target to prevent the virus from reaching the cell body where it could replicate?

Accepted Answer

A)   dynein
B)   kinesin
C)   microtubules
D)   dynein and microtubules

Question 19

The resting membrane potential is a measure of charge difference across the unstimulated cell membrane. This charge difference can exist because

Accepted Answer

A)   the membrane is permeable to all substances
B)   the membrane has channels that serve as conductors
C)   the membrane has lipid components that serve as an insulator
D)   the membrane is permeable to all substances because of its channels

Question 20

In the synaptic end bulb, the action potential leads to the release of neurotransmitter. What links these two types of signals?

Accepted Answer

A)   The action potential triggers voltage-gated Na+ channels to open and the depolarization causes the vesicle walls to merge with the membrane.
B)   The action potential causes a change in the proteins on the vesicle membranes such that the vesicle binds to the cell membrane and begins exocytosis.
C)   The action potential triggers voltage-gated Ca2+ channels to open and the Ca2+ that flows in starts a cascade of protein reactions that allows exocytosis of the neurotransmitters.
D)   The action potential causes K+ to leave during repolarization and the decrease in K+ concentration triggers vesicles to bind to the membrane, releasing their contents.

Exam 7: The Nervous System and Neuronal Excitability

The doctor taps your leg just below your knee to test your reflexes. Your leg swings out at about the same time you perceive that your leg was tapped because of a

Correct AnswerverifiedShow Answer

Assume the potentials from the following combinations of dendrites reach the axon hillock/trigger zone at the same time. Which combination will have the greatest chance of generating an action potential?

Correct AnswerverifiedShow Answer

How can one tell if action potentials are generated by a threshold or suprathreshold stimuli?

Correct AnswerverifiedShow Answer

Speed of conduction of action potentials along an axon is increased in

Correct AnswerverifiedShow Answer

Summation of postsynaptic potentials determines whether or not an action potential will be generated at the axon hillock. The final amplitude of the summed potentials is dependent upon

Correct AnswerverifiedShow Answer

Which of the following is NOT a type of graded potential?

Correct AnswerverifiedShow Answer

An individual touches a sharp object and cries out in pain, but is unable to pull her hand away from the object. In this situation, the _________ neurons are the most likely reason she cannot respond.

Correct AnswerverifiedShow Answer

How does increasing the extracellular calcium concentration lead to a decrease in excitability?

Correct AnswerverifiedShow Answer

A surgeon is repairing damage to an individual's abdominal area, and accidentally connects a nerve that originally controlled the smooth muscle of the GI tract to the skeletal muscle of the abdominal wall. Hypothesize what might happen in this instance.

Correct AnswerverifiedShow Answer

Retrograde and anterograde transport occur in the

Correct AnswerverifiedShow Answer

You are working with some new neural cells and accidentally spill a few drops of a chemical solution into the petri dish. Shortly afterwards, you notice an increase in graded potentials in the cells. You hypothesize that the channels responsible for these graded potentials are

Correct AnswerverifiedShow Answer

A cell with leak channels that are only permeable to Cl- has been placed in a petri dish. Which of the following statements accurately describes the relationship between the concentration gradient and the Cl- equilibrium potential (ECl) ?

Correct AnswerverifiedShow Answer

A major function of the nervous system is communication that allows our bodies to maintain homeostasis. In many cases reflexes will occur without our awareness. Which function of the nervous system is bypassed in this case?

Correct AnswerverifiedShow Answer

A scientist discovers that a neuron does not have adequate stores of neurotransmitter. What part of the neuron is he observing?

Correct AnswerverifiedShow Answer

In a dendroaxonic synapse the part of the postsynaptic cell receiving the signal is the

Correct AnswerverifiedShow Answer

Saltatory conduction is different from continuous conduction because it

Correct AnswerverifiedShow Answer

An investigator is trying to slow the rate of infection of neurons by the herpes simplex virus. Which of these proteins in the neuron could she target to prevent the virus from reaching the cell body where it could replicate?

Correct AnswerverifiedShow Answer

In the synaptic end bulb, the action potential leads to the release of neurotransmitter. What links these two types of signals?

Correct AnswerverifiedShow Answer

Anionic proteins and phosphates have little influence over the resting membrane potential (RMP) because

Correct AnswerverifiedShow Answer

The resting membrane potential is a measure of charge difference across the unstimulated cell membrane. This charge difference can exist because

Correct AnswerverifiedShow Answer

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A cell with leak channels that are only permeable to Cl^- has been placed in a petri dish. Which of the following statements accurately describes the relationship between the concentration gradient and the Cl^- equilibrium potential (E_Cl) ?

Correct Answer
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