Question 1

For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the

Accepted Answer

A)  depolarization of the neuron. 
B)  hyperpolarization of the neuron. 
C)  replacement of potassium ions with sodium ions. 
D)  replacement of potassium ions with calcium ions. 
E)  neuron switching on its sodium-potassium pump to restore the initial conditions. 
A)  depolarization of the neuron. 
B)  hyperpolarization of the neuron. 
C)  replacement of potassium ions with sodium ions. 
D)  replacement of potassium ions with calcium ions. 
E)  neuron switching on its sodium-potassium pump to restore the initial conditions.

Question 2

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 3

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 4

Please use the following information to answer the question(s) below.
The Arizona bark scorpion is the most venomous scorpion in North America, and its bite will cause extensive pain to a human that lasts up to three days. However, the southern grasshopper mouse is essentially immune to the sting of this scorpion and actually eats the scorpions as prey. Researchers have recently elucidated the neuronal reason for why the southern grasshopper mouse does not feel pain from bark scorpion venom.
-The southern grasshopper mouse essentially does not feel pain when stung by the bark scorpion. What type of neuron is most likely blocked in this scenario?

Accepted Answer

A)  interneuron 
B)  motor neuron 
C)  sensory neuron 
D)  glial cells 
A)  interneuron 
B)  motor neuron 
C)  sensory neuron 
D)  glial cells

Question 5

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of a

Accepted Answer

A)  voltage-gated sodium channel. 
B)  voltage-gated potassium channel. 
C)  ligand-gated sodium channel. 
D)  second-messenger-gated sodium channel. 
E)  chemical that inhibits action potentials. 
A)  voltage-gated sodium channel. 
B)  voltage-gated potassium channel. 
C)  ligand-gated sodium channel. 
D)  second-messenger-gated sodium channel. 
E)  chemical that inhibits action potentials.

Question 6

Where are neurotransmitter receptors located?

Accepted Answer

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

Question 7

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 8

Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly

Accepted Answer

A)  refractory. 
B)  fully depolarized. 
C)  above threshold. 
D)  at the equilibrium potential. 
A)  refractory. 
B)  fully depolarized. 
C)  above threshold. 
D)  at the equilibrium potential.

Question 9

Please use the following information to answer the question(s) below.
Curare is a potent neurotoxin extracted from the Strychnos toxifera plant in Central and South America. Indigenous peoples of South America apply curare to arrows, which they used to hunt and kill animals. Curare acts at synapses between motor neurons and skeletal muscle cells. When a motor neuron synapses with a skeletal muscle cell, the skeletal muscle cell may be stimulated or inhibited just like postsynaptic neurons are. Curare acts by binding temporarily to acetylcholine receptors on the postsynaptic cell and prevents acetylcholine from binding.
-Which of the following could be an effective treatment for curare poisoning?

Accepted Answer

A)  a drug that promotes acetylcholine reuptake into the presynaptic cells 
B)  a drug that removes acetylcholine receptors from the postsynaptic cell 
C)  a drug that inhibits acetylcholinesterase 
D)  a drug that activates acetylcholinesterase 
A)  a drug that promotes acetylcholine reuptake into the presynaptic cells 
B)  a drug that removes acetylcholine receptors from the postsynaptic cell 
C)  a drug that inhibits acetylcholinesterase 
D)  a drug that activates acetylcholinesterase

Question 10

Somatic motor neurons are used to transmit motor signals to muscles. For example, a somatic motor neuron carries a signal from your spinal cord to your biceps brachii so that you can flex your arm at the elbow. In this example, what is the correct sequence of neuronal structures that this signal would travel through in the motor neuron?

Accepted Answer

A)  dendrites, cell body, axon, axon hillock, synaptic terminals, biceps brachii 
B)  dendrites, cell body, axon hillock, axon, synaptic terminals, biceps brachii 
C)  axon, cell body, synaptic terminals, dendrites, axon hillock, biceps brachii 
D)  synaptic terminals, dendrites, cell body, axon, axon hillock, biceps brachii 
A)  dendrites, cell body, axon, axon hillock, synaptic terminals, biceps brachii 
B)  dendrites, cell body, axon hillock, axon, synaptic terminals, biceps brachii 
C)  axon, cell body, synaptic terminals, dendrites, axon hillock, biceps brachii 
D)  synaptic terminals, dendrites, cell body, axon, axon hillock, biceps brachii

Question 11

An action potential can start in the middle of an axon and proceed to both opposite directions when

Accepted Answer

A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold. 
A)  the neuron is an inhibitory neuron and operating normally. 
B)  only the middle section of the axon has been artificially stimulated by an electrode. 
C)  the dendritic region fires an action potential. 
D)  it is in its typical refractory state. 
E)  its membrane potential is above the threshold.

Question 12

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 13

Saltatory conduction is a term applied to

Accepted Answer

A)  conduction of impulses across electrical synapses. 
B)  an action potential that skips the axon hillock when it moves from the dendritic region to the axon terminal. 
C)  the rapid movement of an action potential reverberating back and forth along a neuron. 
D)  jumping from one neuron to an adjacent neuron. 
E)  jumping from one node of Ranvier to the next in a myelinated neuron. 
A)  conduction of impulses across electrical synapses. 
B)  an action potential that skips the axon hillock when it moves from the dendritic region to the axon terminal. 
C)  the rapid movement of an action potential reverberating back and forth along a neuron. 
D)  jumping from one neuron to an adjacent neuron. 
E)  jumping from one node of Ranvier to the next in a myelinated neuron.

Question 14

The heart rate decreases in response to the arrival of

Accepted Answer

A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA. 
A)  acetylcholine. 
B)  epinephrine. 
C)  endorphin. 
D)  nitric oxide. 
E)  GABA.

Question 15

Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, then

Accepted Answer

A)  no action potential will be initiated. 
B)  an action potential will be initiated and proceed only in the normal direction toward the axon terminal. 
C)  an action potential will be initiated and proceed only back toward the axon hillock. 
D)  two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock. 
E)  an action potential will be initiated, but it will die out before it reaches the axon terminal. 
A)  no action potential will be initiated. 
B)  an action potential will be initiated and proceed only in the normal direction toward the axon terminal. 
C)  an action potential will be initiated and proceed only back toward the axon hillock. 
D)  two action potentials will be initiated, one going toward the axon terminal and one going back toward the hillock. 
E)  an action potential will be initiated, but it will die out before it reaches the axon terminal.

Question 16

Two fundamental principles that characterize gated ion channels in the neuronal membrane 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.

Exam 37: Neurons, Synapses, and Signaling

For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the

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

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

The observation that the acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is an example of a

Where are neurotransmitter receptors located?

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

Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly

An action potential can start in the middle of an axon and proceed to both opposite directions when

A simple nervous system

Saltatory conduction is a term applied to

The heart rate decreases in response to the arrival of

Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, then

Two fundamental principles that characterize gated ion channels in the neuronal membrane are that the channels

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