Question 1

A postsynaptic cell's processing of information from synapses at different sites is called

Accepted Answer

A)  excitatory postsynaptic potential. 
B)  inhibitory postsynaptic potential. 
C)  spatial summation. 
D)  temporal summation. 
E)  action potential. 
A)  excitatory postsynaptic potential. 
B)  inhibitory postsynaptic potential. 
C)  spatial summation. 
D)  temporal summation. 
E)  action potential. C

Question 2

Special glial cells, called _______, surround the smallest, most permeable blood vessels in the brain, thereby participating in the formation of the blood-brain barrier.

Accepted Answer

astrocytes

Question 3

Which of the following statements about the nervous system is false?

Accepted Answer

A)  It is the most complex system of the human body. 
B)  Oligodendrocytes cover the axons of neurons in the peripheral nervous system. 
C)  Effectors are muscles or glands. 
D)  Sensory cells transduce information into electric signals that can be transmitted by neurons. 
E)  Thousands of synapses impinge on most neurons. 
A)  It is the most complex system of the human body. 
B)  Oligodendrocytes cover the axons of neurons in the peripheral nervous system. 
C)  Effectors are muscles or glands. 
D)  Sensory cells transduce information into electric signals that can be transmitted by neurons. 
E)  Thousands of synapses impinge on most neurons. B

Question 4

When you decide to mark a particular answer to this question, and your nervous system sends the comm­and to your hand to do so, the command is carried by

Accepted Answer

A)  afferent neurons. 
B)  efferent neurons. 
C)  nodes. 
D)  glial cells. 
E)  None of the above 
A)  afferent neurons. 
B)  efferent neurons. 
C)  nodes. 
D)  glial cells. 
E)  None of the above

Question 5

Which of the following statements about synapses is false?

Accepted Answer

A)  Electrical synapses allow electrical signals to pass between cells without the use of neurotransmitters. 
B)  There are many different neurotransmitters and even more types of receptors. 
C)  Some poisons and drugs act by increasing the rate of clearance of transmitter for the synapse. 
D)  The action of a neurotransmitter depends on the receptor to which it binds. 
E)  With repeated stimulation, a neuron can become more sensitive to its inputs. 
A)  Electrical synapses allow electrical signals to pass between cells without the use of neurotransmitters. 
B)  There are many different neurotransmitters and even more types of receptors. 
C)  Some poisons and drugs act by increasing the rate of clearance of transmitter for the synapse. 
D)  The action of a neurotransmitter depends on the receptor to which it binds. 
E)  With repeated stimulation, a neuron can become more sensitive to its inputs.

Question 6

What determines when an individual neuron will fire an action potential?

Accepted Answer

A)  Resting membrane potential 
B)  Inhibitory inputs 
C)  When the sum of all the inputs reaches threshold 
D)  Excitatory stimulation 
E)  When it receives at least 1,000 synaptic inputs 
A)  Resting membrane potential 
B)  Inhibitory inputs 
C)  When the sum of all the inputs reaches threshold 
D)  Excitatory stimulation 
E)  When it receives at least 1,000 synaptic inputs

Question 7

Which of the following statements about electrical synapses is false?

Accepted Answer

A)  Connexons form molecular tunnels between two cells. 
B)  Electrical synapses cannot be inhibitory. 
C)  Electrical synapses do not allow for temporal summation. 
D)  Their transmission capacity is very slow. 
E)  They allow for transmission either toward or away from the cell. 
A)  Connexons form molecular tunnels between two cells. 
B)  Electrical synapses cannot be inhibitory. 
C)  Electrical synapses do not allow for temporal summation. 
D)  Their transmission capacity is very slow. 
E)  They allow for transmission either toward or away from the cell.

Question 8

A neuron that has just fired an action potential cannot be immediately restimulated to fire a second action potential. The short interval of time during which restimulation is not possible is called

Accepted Answer

A)  hyperpolarization. 
B)  the resting potential. 
C)  depolarization. 
D)  repolarization. 
E)  the refractory period. 
A)  hyperpolarization. 
B)  the resting potential. 
C)  depolarization. 
D)  repolarization. 
E)  the refractory period.

Question 9

Which of the following statements about neurons is true?

Accepted Answer

A)  They fire action potentials only on the basis of the number of excitatory inputs they receive. 
B)  They sum excitatory and inhibitory postsynaptic potentials. 
C)  The "decision" to fire is made in the dendrites. 
D)  They make spatial, but not temporal, summations. 
E)  Both a and c 
A)  They fire action potentials only on the basis of the number of excitatory inputs they receive. 
B)  They sum excitatory and inhibitory postsynaptic potentials. 
C)  The "decision" to fire is made in the dendrites. 
D)  They make spatial, but not temporal, summations. 
E)  Both a and c

Question 10

The sodium-potassium pump

Accepted Answer

A)  needs energy to work. 
B)  moves potassium ions to the inside of a neuron and sodium ions to the outside. 
C)  works against a concentration gradient. 
D)  All of the above 
E)  None of the above 
A)  needs energy to work. 
B)  moves potassium ions to the inside of a neuron and sodium ions to the outside. 
C)  works against a concentration gradient. 
D)  All of the above 
E)  None of the above

Question 11

Clinical depression is thought to be due, in part, to insufficient levels of the neurotransmitter serotonin. Drugs known as selective serotonin reuptake inhibitors (SSRIs) can be used to treat depression. Taking the name of this class of drugs as a clue, propose a mechanism by which they might act.

Accepted Answer

Selective serotonin reuptake i

Question 12

Whether a synapse is excitatory or inhibitory depends on the

Accepted Answer

A)  type of neurotransmitter. 
B)  presynaptic axon terminal. 
C)  size of the synapse. 
D)  nature of the postsynaptic receptors. 
E)  concentration of neurotransmitter in the synaptic space. 
A)  type of neurotransmitter. 
B)  presynaptic axon terminal. 
C)  size of the synapse. 
D)  nature of the postsynaptic receptors. 
E)  concentration of neurotransmitter in the synaptic space.

Question 13

The resting potential of a neuron is produced by

Accepted Answer

A)  voltage-gated channels in the membrane. 
B)  chemically gated channels in the membrane. 
C)  potassium channels in the membrane that are permanently open. 
D)  the concentration difference in Na+ across the membrane. 
E)  blockage of the sodium-potassium pump. 
A)  voltage-gated channels in the membrane. 
B)  chemically gated channels in the membrane. 
C)  potassium channels in the membrane that are permanently open. 
D)  the concentration difference in Na+ across the membrane. 
E)  blockage of the sodium-potassium pump.

Question 14

The extensions of postsynaptic neurons that provide the main receptive surface for presynaptic neurons are the

Accepted Answer

A)  nuclei. 
B)  somas. 
C)  axons. 
D)  dendrites. 
E)  glia. 
A)  nuclei. 
B)  somas. 
C)  axons. 
D)  dendrites. 
E)  glia.

Question 15

The myelin sheath that surrounds some axons in the peripheral nervous system is formed by

Accepted Answer

A)  neurons. 
B)  Schwann cells. 
C)  bacteria that have invaded the nervous system. 
D)  synapses. 
E)  None of the above 
A)  neurons. 
B)  Schwann cells. 
C)  bacteria that have invaded the nervous system. 
D)  synapses. 
E)  None of the above

Question 16

Use the following to answer questions:
Refer to the graph below, showing the course of an action potential.  
-In the action potential shown, which of the following cellular events is mispaired with the position at which it occurs?

Accepted Answer

A)  Position 1 - Voltage-gated sodium channels are closed 
B)  Position 2 - Activation gates of some sodium channels open 
C)  Position 3 - Voltage-gated potassium channels close 
D)  Position 4 - Inactivation gates of sodium channels close 
E)  Position 5 - Inactivation gates of sodium channels reopen 
A)  Position 1 - Voltage-gated sodium channels are closed 
B)  Position 2 - Activation gates of some sodium channels open 
C)  Position 3 - Voltage-gated potassium channels close 
D)  Position 4 - Inactivation gates of sodium channels close 
E)  Position 5 - Inactivation gates of sodium channels reopen

Question 17

Neurons that transmit information from sensory cells to the central nervous system are part of the

Accepted Answer

A)  brain. 
B)  peripheral nervous system. 
C)  central nervous system. 
D)  spinal cord. 
E)  nerve net. 
A)  brain. 
B)  peripheral nervous system. 
C)  central nervous system. 
D)  spinal cord. 
E)  nerve net.

Question 18

Some organisms, such as earthworms and squid, have clusters of neurons called

Accepted Answer

A)  the spinal cord. 
B)  the central nervous system. 
C)  the peripheral nervous system. 
D)  ganglia. 
E)  None of the above 
A)  the spinal cord. 
B)  the central nervous system. 
C)  the peripheral nervous system. 
D)  ganglia. 
E)  None of the above

Question 19

Action potentials travel faster in _______ axons.

Accepted Answer

A)  myelinated 
B)  unmyelinated 
C)  small diameter 
D)  Both a and c 
E)  Both b and c 
A)  myelinated 
B)  unmyelinated 
C)  small diameter 
D)  Both a and c 
E)  Both b and c

Question 20

The depolarization of the presynaptic membrane of an axon terminal most directly causes

Accepted Answer

A)  voltage-gated calcium channels in the membrane to open. 
B)  synaptic vesicles to fuse with the membrane. 
C)  an action potential in the postsynaptic cell. 
D)  the opening of chemically sensitive gates that allow neurotransmitter to spill into the synaptic cleft. 
E)  neurotransmitter to bind to receptors on the postsynaptic membrane. 
A)  voltage-gated calcium channels in the membrane to open. 
B)  synaptic vesicles to fuse with the membrane. 
C)  an action potential in the postsynaptic cell. 
D)  the opening of chemically sensitive gates that allow neurotransmitter to spill into the synaptic cleft. 
E)  neurotransmitter to bind to receptors on the postsynaptic membrane.

Exam 45: Neurons and Nervous Systems

A postsynaptic cell's processing of information from synapses at different sites is called

Special glial cells, called _______, surround the smallest, most permeable blood vessels in the brain, thereby participating in the formation of the blood-brain barrier.

Which of the following statements about the nervous system is false?

When you decide to mark a particular answer to this question, and your nervous system sends the comm­and to your hand to do so, the command is carried by

Which of the following statements about synapses is false?

What determines when an individual neuron will fire an action potential?

Which of the following statements about electrical synapses is false?

A neuron that has just fired an action potential cannot be immediately restimulated to fire a second action potential. The short interval of time during which restimulation is not possible is called

Which of the following statements about neurons is true?

The sodium-potassium pump

Clinical depression is thought to be due, in part, to insufficient levels of the neurotransmitter serotonin. Drugs known as selective serotonin reuptake inhibitors (SSRIs) can be used to treat depression. Taking the name of this class of drugs as a clue, propose a mechanism by which they might act.

Whether a synapse is excitatory or inhibitory depends on the

The resting potential of a neuron is produced by

The extensions of postsynaptic neurons that provide the main receptive surface for presynaptic neurons are the

The myelin sheath that surrounds some axons in the peripheral nervous system is formed by

Use the following to answer questions: Refer to the graph below, showing the course of an action potential. -In the action potential shown, which of the following cellular events is mispaired with the position at which it occurs?

Neurons that transmit information from sensory cells to the central nervous system are part of the

Some organisms, such as earthworms and squid, have clusters of neurons called

Action potentials travel faster in _______ axons.

The depolarization of the presynaptic membrane of an axon terminal most directly causes

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