Question 1

A cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is

Accepted Answer

A) HCO₃⁻. 
B) Cl⁻. 
C) Ca⁺⁺. 
D) Na⁺. 
E) K⁺. 
A) HCO₃⁻. 
B) Cl⁻. 
C) Ca⁺⁺. 
D) Na⁺. 
E) K⁺. E

Question 2

Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?

Accepted Answer

A) Voltage-gated calcium channels in the membrane open. 
B) Synaptic vesicles fuse with the membrane. 
C) The postsynaptic cell produces an action potential. 
D) Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. 
E) An EPSP or IPSP is generated in the postsynaptic cell. 
A) Voltage-gated calcium channels in the membrane open. 
B) Synaptic vesicles fuse with the membrane. 
C) The postsynaptic cell produces an action potential. 
D) Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. 
E) An EPSP or IPSP is generated in the postsynaptic cell. A

Question 3

The point of connection between two communicating neurons is called

Accepted Answer

A) the axon hillock. 
B) the dendrite. 
C) the synapse. 
D) the cell body. 
E) the glia. 
A) the axon hillock. 
B) the dendrite. 
C) the synapse. 
D) the cell body. 
E) the glia. C

Question 4

A toxin that binds specifically to voltage-gated sodium channels in axons would be expected to

Accepted Answer

A) prevent the hyperpolarization phase of the action potential. 
B) prevent the depolarization phase of the action potential. 
C) prevent graded potentials. 
D) increase the release of neurotransmitter molecules. 
E) have most of its effects on the dendritic region of a neuron. 
A) prevent the hyperpolarization phase of the action potential. 
B) prevent the depolarization phase of the action potential. 
C) prevent graded potentials. 
D) increase the release of neurotransmitter molecules. 
E) have most of its effects on the dendritic region of a neuron.

Question 5

In the sequence of permeability changes for a complete action potential,the first of these events that occurs is

Accepted Answer

A) the activation of the sodium-potassium "pump." 
B) the inhibition of the sodium-potassium "pump." 
C) the opening of voltage-gated sodium channels. 
D) the closing of voltage-gated potassium channels. 
E) the opening of voltage-gated potassium channels. 
A) the activation of the sodium-potassium "pump." 
B) the inhibition of the sodium-potassium "pump." 
C) the opening of voltage-gated sodium channels. 
D) the closing of voltage-gated potassium channels. 
E) the opening of voltage-gated potassium channels.

Question 6

The surface on a neuron that discharges the contents of synaptic vesicles is the

Accepted Answer

A) dendrite. 
B) axon hillock. 
C) node of Ranvier. 
D) postsynaptic membrane. 
E) presynaptic membrane. 
A) dendrite. 
B) axon hillock. 
C) node of Ranvier. 
D) postsynaptic membrane. 
E) presynaptic membrane.

Question 7

A common feature of action potentials is that they

Accepted Answer

A) cause the membrane to hyperpolarize and then depolarize. 
B) can undergo temporal and spatial summation. 
C) are triggered by a depolarization that reaches the threshold. 
D) move at the same speed along all axons. 
E) require the diffusion of Na⁺ and K⁺ through ligand-gated channels to propagate. 
A) cause the membrane to hyperpolarize and then depolarize. 
B) can undergo temporal and spatial summation. 
C) are triggered by a depolarization that reaches the threshold. 
D) move at the same speed along all axons. 
E) require the diffusion of Na⁺ and K⁺ through ligand-gated channels to propagate.

Question 8

The primary means by which a neuron can communicate to a second neuron is by

Accepted Answer

A) the frequency of its action potentials. 
B) the peak of the depolarization phase of an action potential. 
C) the peak of the undershoot/hyperpolarization of an action potential. 
D) varying how much neurotransmitter it releases for a given action potential. 
E) remaining in the depolarization phase of the action potential for an extended interval. 
A) the frequency of its action potentials. 
B) the peak of the depolarization phase of an action potential. 
C) the peak of the undershoot/hyperpolarization of an action potential. 
D) varying how much neurotransmitter it releases for a given action potential. 
E) remaining in the depolarization phase of the action potential for an extended interval.

Question 9

Functionally,which cellular location is the neuron's "decision-making site" as to whether or not an action potential will be initiated?

Accepted Answer

A) axonal membranes 
B) axon hillocks 
C) dendritic membranes 
D) mitochondrial membranes 
E) presynaptic membranes 
A) axonal membranes 
B) axon hillocks 
C) dendritic membranes 
D) mitochondrial membranes 
E) presynaptic membranes

Question 10

Where are neurotransmitter receptors located?

Accepted Answer

A) the nuclear membrane 
B) the nodes of Ranvier 
C) the postsynaptic membrane 
D) synaptic vesicle membranes 
E) the myelin sheath 
A) the nuclear membrane 
B) the nodes of Ranvier 
C) the postsynaptic membrane 
D) synaptic vesicle membranes 
E) the myelin sheath

Question 11

In the communication between a motor neuron and a skeletal muscle

Accepted Answer

A) the motor neuron is considered the presynaptic cell and the skeletal muscle is the postsynaptic cell. 
B) the motor neuron is considered the postsynaptic cell and the skeletal muscle is the presynaptic cell. 
C) action potentials are possible on the motor neuron but not the skeletal muscle. 
D) action potentials are possible on the skeletal muscle but not the motor neuron. 
E) the motor neuron fires action potentials but the skeletal muscle is not electrochemically excitable. 
A) the motor neuron is considered the presynaptic cell and the skeletal muscle is the postsynaptic cell. 
B) the motor neuron is considered the postsynaptic cell and the skeletal muscle is the presynaptic cell. 
C) action potentials are possible on the motor neuron but not the skeletal muscle. 
D) action potentials are possible on the skeletal muscle but not the motor neuron. 
E) the motor neuron fires action potentials but the skeletal muscle is not electrochemically excitable.

Question 12

For the following questions,refer to the graph of an action potential.
  
-The membrane potential is closest to the equilibrium potential for potassium at label

Accepted Answer

A) 
A)  
B) 
B)  
C) 
C)  
D) 
D)  
E) 
E)  
A) 
A)  
B) 
B)  
C) 
C)  
D) 
D)  
E) 
E)

Question 13

ATP hydrolysis directly powers the movement of

Accepted Answer

A) K⁺ out of cells. 
B) Na⁺ out of cells. 
C) Na⁺ into cells. 
D) Ca⁺⁺ into cells. 
E) Cl⁻ into cells. 
A) K⁺ out of cells. 
B) Na⁺ out of cells. 
C) Na⁺ into cells. 
D) Ca⁺⁺ into cells. 
E) Cl⁻ into cells.

Question 14

The "threshold" potential of a membrane

Accepted Answer

A) is the point of separation from a living to a dead neuron. 
B) is the lowest frequency of action potentials a neuron can produce. 
C) is the minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D) is the minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E) is the peak amount of depolarization seen in an action potential. 
A) is the point of separation from a living to a dead neuron. 
B) is the lowest frequency of action potentials a neuron can produce. 
C) is the minimum hyperpolarization needed to prevent the occurrence of action potentials. 
D) is the minimum depolarization needed to operate the voltage-gated sodium and potassium channels. 
E) is the peak amount of depolarization seen in an action potential.

Question 15

Although the membrane of a "resting" neuron is highly permeable to potassium ions,its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

Accepted Answer

A) fully permeable to sodium ions. 
B) slightly permeable to sodium ions. 
C) fully permeable to calcium ions. 
D) impermeable to sodium ions. 
E) highly permeable to chloride ions. 
A) fully permeable to sodium ions. 
B) slightly permeable to sodium ions. 
C) fully permeable to calcium ions. 
D) impermeable to sodium ions. 
E) highly permeable to chloride ions.

Question 16

An example of the action of metabotropic receptors occurs when

Accepted Answer

A) voltage-gated ion channels open. 
B) voltage-gated ion channels close. 
C) acetylcholine-gated sodium channels open. 
D) cAMP-linked ion channels open. 
E) the undershoot/after-hyperpolarization occurs. 
A) voltage-gated ion channels open. 
B) voltage-gated ion channels close. 
C) acetylcholine-gated sodium channels open. 
D) cAMP-linked ion channels open. 
E) the undershoot/after-hyperpolarization occurs.

Question 17

What happens if a neuron is stimulated enough midway in an axon to trigger an action potential?

Accepted Answer

A) The nerve impulse would go both directions from the stimulus point, but only the axon end could transfer the message through neurotransmitters to another neuron. 
B) Since neuron transmission is one-way, the nerve impulse would only be transmitted to the end of the axon and then through neurotransmitters to the next neuron. 
C) The nerve impulse could not be transmitted because it must be initiated at the pre-synaptic end of a neuron. 
D) The nerve impulse would go both directions and the pre-synaptic end would be stimulated to send a second message through this neuron. 
E) The nerve impulse would go both directions from the stimulus point, and both ends of the neuron would transmit the message to adjacent neurons. 
A) The nerve impulse would go both directions from the stimulus point, but only the axon end could transfer the message through neurotransmitters to another neuron. 
B) Since neuron transmission is one-way, the nerve impulse would only be transmitted to the end of the axon and then through neurotransmitters to the next neuron. 
C) The nerve impulse could not be transmitted because it must be initiated at the pre-synaptic end of a neuron. 
D) The nerve impulse would go both directions and the pre-synaptic end would be stimulated to send a second message through this neuron. 
E) The nerve impulse would go both directions from the stimulus point, and both ends of the neuron would transmit the message to adjacent neurons.

Question 18

Assume that a single IPSP has a negative magnitude of -0.5 mV at the axon hillock and that a single EPSP has a positive magnitude of +0.5 mV.For a neuron with an initial membrane potential of -70 mV,the net effect of the simultaneous arrival of six IPSPs and two EPSPs would be to move the membrane potential to

Accepted Answer

A) -72 mV. 
B) -71 mV. 
C) -70 mV. 
D) -69 mV. 
E) -68 mV. 
A) -72 mV. 
B) -71 mV. 
C) -70 mV. 
D) -69 mV. 
E) -68 mV.

Question 19

In certain large animals,this type of neuron can extend beyond 1 metre in length.

Accepted Answer

A) glial cell in the brain 
B) a motor neuron 
C) an interneuron 
D) a glial cell at a ganglion 
E) a neuron that controls eye movements 
A) glial cell in the brain 
B) a motor neuron 
C) an interneuron 
D) a glial cell at a ganglion 
E) a neuron that controls eye movements

Question 20

After the depolarization phase of an action potential,the resting potential is restored by

Accepted Answer

A) the opening of sodium activation gates. 
B) the opening of voltage-gated potassium channels and the closing of sodium channels. 
C) a decrease in the membrane's permeability to potassium and chloride ions. 
D) a brief inhibition of the sodium-potassium pump. 
E) the opening of more voltage-gated sodium channels. 
A) the opening of sodium activation gates. 
B) the opening of voltage-gated potassium channels and the closing of sodium channels. 
C) a decrease in the membrane's permeability to potassium and chloride ions. 
D) a brief inhibition of the sodium-potassium pump. 
E) the opening of more voltage-gated sodium channels.

Exam 48: Neurons,Synapses,and Signalling

A cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is

Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?

The point of connection between two communicating neurons is called

A toxin that binds specifically to voltage-gated sodium channels in axons would be expected to

In the sequence of permeability changes for a complete action potential,the first of these events that occurs is

The surface on a neuron that discharges the contents of synaptic vesicles is the

A common feature of action potentials is that they

The primary means by which a neuron can communicate to a second neuron is by

Functionally,which cellular location is the neuron's "decision-making site" as to whether or not an action potential will be initiated?

Where are neurotransmitter receptors located?

In the communication between a motor neuron and a skeletal muscle

For the following questions,refer to the graph of an action potential. -The membrane potential is closest to the equilibrium potential for potassium at label

ATP hydrolysis directly powers the movement of

The "threshold" potential of a membrane

Although the membrane of a "resting" neuron is highly permeable to potassium ions,its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also

An example of the action of metabotropic receptors occurs when

What happens if a neuron is stimulated enough midway in an axon to trigger an action potential?

In certain large animals,this type of neuron can extend beyond 1 metre in length.

After the depolarization phase of an action potential,the resting potential is restored by

Introduction: Evolution and Themes of Biology

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