Question 1

Motor neurons alter skeletal muscle activities by releasing neurotransmitters because

Accepted Answer

A) they are electrically coupled by gap junctions to the muscles. 
B) their signals bind to receptor proteins on the muscles. 
C) their signals reach the muscles via the blood. 
D) their light pulses activate contraction in the muscles. 
E) they are connected to the internal neural network of the muscles. 
A) they are electrically coupled by gap junctions to the muscles. 
B) their signals bind to receptor proteins on the muscles. 
C) their signals reach the muscles via the blood. 
D) their light pulses activate contraction in the muscles. 
E) they are connected to the internal neural network of the muscles.

Question 2

An endorphin is

Accepted Answer

A) a chemical that affects neuronal function but is not stored in presynaptic vesicles. 
B) an amino acid that operates at inhibitory synapses in the brain. 
C) a neuropeptide that might function as a natural analgesic. 
D) the major inhibitory neurotransmitter of the human brain. 
A) a chemical that affects neuronal function but is not stored in presynaptic vesicles. 
B) an amino acid that operates at inhibitory synapses in the brain. 
C) a neuropeptide that might function as a natural analgesic. 
D) the major inhibitory neurotransmitter of the human brain.

Question 3

Please use the following information to answer the questions below.
Tetraethylammonium (TEA)is a potent neurotoxin that results in death from respiratory failure within 10 to 30 minutes.When a neuron is incubated with TEA,researchers observed that action potentials could be generated,but the membrane potential remained positive and never returned to the resting membrane potential.
-What channel is TEA likely acting on?

Accepted Answer

A) voltage-gated sodium channels 
B) voltage-gated potassium channels 
C) sodium potassium pumps 
D) chloride channels 
A) voltage-gated sodium channels 
B) voltage-gated potassium channels 
C) sodium potassium pumps 
D) chloride channels

Question 4

If a membrane is made more permeable to ________,then an inhibitory postsynaptic potential (IPSP)will occur.

Accepted Answer

A) potassium ions 
B) sodium ions 
C) calcium ions 
A) potassium ions 
B) sodium ions 
C) calcium ions

Question 5

Figure 37.2
-Figure 37.2 shows many channels in a neuron membrane.The channel third from the left is a voltage-gated sodium channel.What would happen if this channel became blocked and thus unable to function?

Accepted Answer

A) The cell's membrane potential would not change. 
B) The cell would hyperpolarize. 
C) The cell would depolarize. 
A) The cell's membrane potential would not change. 
B) The cell would hyperpolarize. 
C) The cell would depolarize.

Question 6

Neurons can be classified according to structure as well as function.If a neuron has a single projection from the cell body,it is a unipolar neuron.If it has two projections,it is a bipolar neuron.Finally,if it has more than two projections,it is a multipolar neuron.What structural type of neuron is a motor neuron?

Accepted Answer

A) unipolar neuron 
B) bipolar neuron 
C) multipolar neuron 
A) unipolar neuron 
B) bipolar neuron 
C) multipolar neuron

Question 7

The operation of the sodium-potassium "pump" moves sodium ions ________ the cell and potassium ions ________ the cell.

Accepted Answer

A) into;out of 
B) out of;into 
C) into;into 
D) out of;out of 
A) into;out of 
B) out of;into 
C) into;into 
D) out of;out of

Question 8

Researchers injected bark scorpion venom in mouse neurons (both a common house mouse and the southern grasshopper mouse)and measured the flow of sodium ions across the cell membrane.Their data are shown below.   Based on these data,what effect do you think the venom is having on the grasshopper mouse?

Accepted Answer

A) The venom is blocking voltage-gated sodium channels. 
B) The venom is blocking voltage-gated potassium channels. 
C) The venom is opening voltage-gated sodium channels. 
D) The venom is opening voltage-gated potassium channels. 
A) The venom is blocking voltage-gated sodium channels. 
B) The venom is blocking voltage-gated potassium channels. 
C) The venom is opening voltage-gated sodium channels. 
D) The venom is opening voltage-gated potassium channels.

Question 9

The "undershoot" phase of after-hyperpolarization is due to

Accepted Answer

A) slow opening of voltage-gated sodium channels. 
B) sustained opening of voltage-gated potassium channels. 
C) rapid opening of voltage-gated calcium channels. 
D) slow restorative actions of the sodium-potassium ATPase. 
E) ions that move away from their open ion channels. 
A) slow opening of voltage-gated sodium channels. 
B) sustained opening of voltage-gated potassium channels. 
C) rapid opening of voltage-gated calcium channels. 
D) slow restorative actions of the sodium-potassium ATPase. 
E) ions that move away from their open ion channels.

Question 10

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) Ca2+. 
D) Na+. 
E) K+. 
A) HCO3-. 
B) Cl-. 
C) Ca2+. 
D) Na+. 
E) K+.

Question 11

The cell body of a neuron contains

Accepted Answer

A) the nucleus and most organelles. 
B) dendrites. 
C) the axon. 
D) synaptic vesicles about to be released at the synapse. 
A) the nucleus and most organelles. 
B) dendrites. 
C) the axon. 
D) synaptic vesicles about to be released at the synapse.

Question 12

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) Ligand-gated channels open,allowing neurotransmitters to enter the synaptic cleft. 
D) 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) Ligand-gated channels open,allowing neurotransmitters to enter the synaptic cleft. 
D) An EPSP or IPSP is generated in the postsynaptic cell.

Question 13

Nitric oxide is

Accepted Answer

A) a chemical that affects neuronal function but is not stored in presynaptic vesicles. 
B) an amino acid that operates at inhibitory synapses in the brain. 
C) a neuropeptide that might function as a natural analgesic. 
D) the major inhibitory neurotransmitter of the human brain. 
A) a chemical that affects neuronal function but is not stored in presynaptic vesicles. 
B) an amino acid that operates at inhibitory synapses in the brain. 
C) a neuropeptide that might function as a natural analgesic. 
D) the major inhibitory neurotransmitter of the human brain.

Question 14

Two fundamental concepts about the ion channels of a "resting" neuron are that the channels

Accepted Answer

A) are always open,but the concentration gradients of ions frequently change. 
B) are always closed,but ions move closer to the channels during excitation. 
C) open and close depending on stimuli and are specific as to which ion can traverse them. 
D) open and close depending on chemical messengers and are nonspecific as to which ion can traverse them. 
E) open in response to stimuli and then close simultaneously,in unison. 
A) are always open,but the concentration gradients of ions frequently change. 
B) are always closed,but ions move closer to the channels during excitation. 
C) open and close depending on stimuli and are specific as to which ion can traverse them. 
D) open and close depending on chemical messengers and are nonspecific as to which ion can traverse them. 
E) open in response to stimuli and then close simultaneously,in unison.

Question 15

A simple nervous system

Accepted Answer

A) must include chemical senses and vision. 
B) includes sensory information but no effectors. 
C) has information flow in only one direction: toward an integrating center. 
D) has information flow in only one direction: away from an integrating center. 
E) includes sensory information,an integrating center,and effectors. 
A) must include chemical senses and vision. 
B) includes sensory information but no effectors. 
C) has information flow in only one direction: toward an integrating center. 
D) has information flow in only one direction: away from an integrating center. 
E) includes sensory information,an integrating center,and effectors.

Question 16

When a membrane is in its refractory period,

Accepted Answer

A) it is not possible to generate a second action potential. 
B) it is at the equilibrium potential. 
C) it is above threshold. 
D) all of its voltage-gated potassium channels are open. 
A) it is not possible to generate a second action potential. 
B) it is at the equilibrium potential. 
C) it is above threshold. 
D) all of its voltage-gated potassium channels are open.

Question 17

Most of the synapses in vertebrates conduct information in only one direction

Accepted Answer

A) as a result of the nodes of Ranvier. 
B) as a result of voltage-gated sodium channels found only in the vertebrate system. 
C) because vertebrate nerve cells have dendrites. 
D) because only the postsynaptic cells can bind and respond to neurotransmitters. 
E) because the sodium-potassium pump moves ions in one direction. 
A) as a result of the nodes of Ranvier. 
B) as a result of voltage-gated sodium channels found only in the vertebrate system. 
C) because vertebrate nerve cells have dendrites. 
D) because only the postsynaptic cells can bind and respond to neurotransmitters. 
E) because the sodium-potassium pump moves ions in one direction.

Exam 37: Neurons,synapses,and Signaling

Motor neurons alter skeletal muscle activities by releasing neurotransmitters because

An endorphin is

If a membrane is made more permeable to ________,then an inhibitory postsynaptic potential (IPSP)will occur.

Figure 37.2 -Figure 37.2 shows many channels in a neuron membrane.The channel third from the left is a voltage-gated sodium channel.What would happen if this channel became blocked and thus unable to function?

The operation of the sodium-potassium "pump" moves sodium ions ________ the cell and potassium ions ________ the cell.

The "undershoot" phase of after-hyperpolarization is due to

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

The cell body of a neuron contains

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

Nitric oxide is

Two fundamental concepts about the ion channels of a "resting" neuron are that the channels

A simple nervous system

When a membrane is in its refractory period,

Most of the synapses in vertebrates conduct information in only one direction

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The operation of the sodium-potassium "pump" moves sodium ions the cell and potassium ions the cell.