Question 1

The function of a myelin sheath is to ____.​

Accepted Answer

A)  prevent action potentials from traveling in the wrong direction
B)  ​increase the velocity of transmission along an axon
C)  ​increase the magnitude of an action potential
D)  provide a store of nutrients for the neuronE) A) and B)
F) B) and C)

Question 2

Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?​

Accepted Answer

A)  if dendrites were generally longer than axons
B)  ​if the glia-to-neuron ratio were higher
C)  ​if selective permeability of the membrane did not exist
D)  if it were an active transport system that required energyE) B) and C)
F) All of the above

Question 3

Glial cells ____.​

Accepted Answer

A)  are less numerous than neurons in the human brain.
B)  ​transmit information over long distances within the central nervous system.
C)  ​occupy about ten times more space in the brain than do neurons.
D)  are smaller but more numerous than neurons in the human brain.E) A) and C)
F) A) and D)

Question 4

Increasing the electrical gradient for potassium will reduce the tendency for potassium ions to exit the neuron.​

Accepted Answer

A) True 
 B)False

Question 5

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their ____.​

Accepted Answer

A)  permeability
B)  ​length
C)  ​number
D)  thresholdE) A) and B)
F) B) and C)

Question 6

According to the all-or-none law,____.​

Accepted Answer

A)  all neurons produce an action potential at the same time or none at all
B)  ​all of the extracellular sodium enters the axon, or none at all
C)  ​once an axon reaches threshold, the amplitude and velocity of an action potential are nearly equal each time
D)  neurons are either active all the time or not at allE) A) and B)
F) C) and D) C

Question 7

When the neuronal membrane is at rest,the sodium channels ____.​

Accepted Answer

A)  permit sodium ions to pass quickly and easily
B)  ​are at equilibrium with potassium channels
C)  ​are closed, so there is almost no flow of sodium
D)  allow sodium to leak out as a steady, continuous dripE) C) and D)
F) B) and C)

Question 8

A prolonged increase in the permeability of the membrane to sodium ions would interfere with a neuron's ability to have an action potential.​

Accepted Answer

A) True 
 B)False

Question 9

Why does the brain need thiamine?​

Accepted Answer

A)  to enable glucose to cross the blood-brain barrier
B)  ​as a source of fuel in case there is not enough glucose
C)  ​as a building block for making proteins
D)  to enable it to metabolize glucoseE) B) and C)
F) All of the above

Question 10

An efferent axon carries information away from a structure.​

Accepted Answer

A) True 
 B)False

Question 11

At what point do the sodium gates begin to close,shutting out further entry of sodium into the cell?​

Accepted Answer

A)  at the peak of the action potential
B)  ​when the threshold is reached
C)  ​at the end of the relative refractory period
D)  when the concentration gradient for sodium is eliminatedE) A) and D)
F) All of the above

Question 12

Explain the function and process of a neuron's refractory period.​

Accepted Answer

Although the electrical potential across...

Question 13

Neurons differ most strongly from other body cells in their ____.​

Accepted Answer

A)  temperature
B)  ​shape
C)  ​osmotic pressure
D)  mitochondriaE) B) and D)
F) All of the above

Question 14

A presynaptic terminal is also known as ____.​

Accepted Answer

A)  an end bulb
B)  ​a node of Ranvier
C)  ​myelin
D)  a spineE) A) and B)
F) None of the above

Question 15

Radial glia ____.​

Accepted Answer

A)  guide the migration of neurons during embryonic development
B)  ​synchronize the activity of axons
C)  ​wrap around the presynaptic terminals of several axons
D)  build the myelin sheaths that surround and insulate certain axonsE) B) and D)
F) A) and B) A

Question 16

Which of the following describes selective permeability?​

Accepted Answer

A)  Ions can only travel in certain directions across the membrane.
B)  ​Only certain molecules are allowed to cross the membrane freely.
C)  ​Only certain types of stimulation will result in an action potential.
D)  All molecules must pass through designated channels.E) B) and C)
F) A) and C)

Question 17

Many dendrites contain short outgrowths called spines that _____.​

Accepted Answer

A)  increase the surface area available for synapses
B)  ​increase the speed of transmission
C)  ​eliminate cell waste products
D)  increase the symmetry of the cel.E) C) and D)
F) A) and B)

Question 18

At the peak of the action potential,the electrical gradient of potassium ____.​

Accepted Answer

A)  is the same as during the resting potential
B)  ​pulls sodium into the cell
C)  ​pushes potassium out of the cell
D)  pulls potassium into the cellE) A) and C)
F) None of the above

Question 19

Describe the key aspects of the resting potential.​

Accepted Answer

All parts of a neuron are covered by a m...

Question 20

The branching fibers that form the information-receiving pole of the nerve cells are called _____.​

Accepted Answer

A)  motor neurons
B)  ​dendrites
C)  ​sensory neurons
D)  axonsE) A) and D)
F) None of the above B

Exam 1: Nerve Cells and Nerve Impulses

The function of a myelin sheath is to ____.​

Correct AnswerverifiedShow Answer

Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?​

Correct AnswerverifiedShow Answer

Glial cells ____.​

Correct AnswerverifiedShow Answer

Increasing the electrical gradient for potassium will reduce the tendency for potassium ions to exit the neuron.​

Correct AnswerverifiedShow Answer

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their ____.​

Correct AnswerverifiedShow Answer

According to the all-or-none law,____.​

Correct AnswerverifiedC

When the neuronal membrane is at rest,the sodium channels ____.​

Correct AnswerverifiedShow Answer

A prolonged increase in the permeability of the membrane to sodium ions would interfere with a neuron's ability to have an action potential.​

Correct AnswerverifiedShow Answer

Why does the brain need thiamine?​

Correct AnswerverifiedShow Answer

An efferent axon carries information away from a structure.​

Correct AnswerverifiedShow Answer

At what point do the sodium gates begin to close,shutting out further entry of sodium into the cell?​

Correct AnswerverifiedShow Answer

Explain the function and process of a neuron's refractory period.​

Correct AnswerverifiedAlthough the electrical potential across...View AnswerShow Answer

Neurons differ most strongly from other body cells in their ____.​

Correct AnswerverifiedShow Answer

A presynaptic terminal is also known as ____.​

Correct AnswerverifiedShow Answer

Radial glia ____.​

Correct AnswerverifiedA

Which of the following describes selective permeability?​

Correct AnswerverifiedShow Answer

Many dendrites contain short outgrowths called spines that _____.​

Correct AnswerverifiedShow Answer

At the peak of the action potential,the electrical gradient of potassium ____.​

Correct AnswerverifiedShow Answer

Describe the key aspects of the resting potential.​

Correct AnswerverifiedAll parts of a neuron are covered by a m...View AnswerShow Answer

The branching fibers that form the information-receiving pole of the nerve cells are called _____.​

Correct AnswerverifiedB

The function of a myelin sheath is to ____.

Correct Answer
verified

Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?

Correct Answer
verified

Glial cells ____.

Correct Answer
verified

Increasing the electrical gradient for potassium will reduce the tendency for potassium ions to exit the neuron.

Correct Answer
verified

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their ____.

Correct Answer
verified

According to the all-or-none law,____.

Correct Answer
verified
C

When the neuronal membrane is at rest,the sodium channels ____.

Correct Answer
verified

A prolonged increase in the permeability of the membrane to sodium ions would interfere with a neuron's ability to have an action potential.

Correct Answer
verified

Why does the brain need thiamine?

Correct Answer
verified

An efferent axon carries information away from a structure.

Correct Answer
verified

At what point do the sodium gates begin to close,shutting out further entry of sodium into the cell?

Correct Answer
verified

Explain the function and process of a neuron's refractory period.

Correct Answer
verified
Although the electrical potential across...
View Answer

Neurons differ most strongly from other body cells in their ____.

Correct Answer
verified

A presynaptic terminal is also known as ____.

Correct Answer
verified

Radial glia ____.

Correct Answer
verified
A

Which of the following describes selective permeability?

Correct Answer
verified

Many dendrites contain short outgrowths called spines that _____.

Correct Answer
verified

At the peak of the action potential,the electrical gradient of potassium ____.

Correct Answer
verified

Describe the key aspects of the resting potential.

Correct Answer
verified
All parts of a neuron are covered by a m...
View Answer

The branching fibers that form the information-receiving pole of the nerve cells are called _____.

Correct Answer
verified
B