Question 1

The nucleus and most of the organelles in a neuron are located in the

Accepted Answer

A)  dendrites. 
B)  axon hillock. 
C)  axon. 
D)  cell body. 
E)  axon terminals.

Question 2

Researchers injected bark scorpion venom in mouse neurons (both a common house mouse and the southern grasshopper mouse) and measured how many action potentials were generated after the venom was introduced. Their data is 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.

Question 3

In a simple synapse, neurotransmitter chemicals are released by

Accepted Answer

A)  the dendritic membrane. 
B)  the presynaptic membrane. 
C)  axon hillocks. 
D)  cell bodies.

Question 4

A graded hyperpolarization of a membrane can be induced by

Accepted Answer

A)  increasing its membrane's permeability to Na+. 
B)  decreasing its membrane's permeability to H+. 
C)  decreasing its membrane's permeability to Cl-. 
D)  increasing its membrane's permeability to Ca2+. 
E)  increasing its membrane's permeability to K+.

Question 5

Receptors for neurotransmitters are of primary functional importance in assuring one-way synaptic transmission because they are mostly found on the

Accepted Answer

A)  axonal membrane. 
B)  axon hillock. 
C)  postsynaptic dendritic membrane. 
D)  presynaptic membrane.

Question 6

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 threshold. 
D)  move at the same speed along all axons.

Question 7

The point of connection between two communicating neurons is called the

Accepted Answer

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

Question 8

When several excitatory postsynaptic potentials (EPSPs) arrive at the axon hillock from different dendritic locations and then depolarize the postsynaptic cell to threshold for an action potential, this is an example of

Accepted Answer

A)  temporal summation. 
B)  spatial summation. 
C)  a normal action potential. 
D)  an action potential with an abnormally high peak of depolarization.

Question 9

A chemical that affects neuronal function but is not stored in presynaptic vesicles is

Accepted Answer

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

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+.

Question 11

In Figure 37.1, the minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label

Accepted Answer

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

Question 12

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

Accepted Answer

A)  the threshold value in the postsynaptic membrane is different for cell X and cell Y. 
B)  the axon of cell X is myelinated, but that of cell Y is not. 
C)  only cell Y produces an enzyme that terminates the activity of the neurotransmitter. 
D)  cells X and Y express different receptor molecules for this particular neurotransmitter.

Question 13

Assume that excessive consumption of ethanol increases the influx of negative chloride ions into "commonsense" neurons whose action potentials are needed for you to act appropriately and not harm yourself or others. Thus, any resulting poor decisions associated with ethanol ingestion are likely due to

Accepted Answer

A)  increased membrane depolarization of "commonsense" neurons. 
B)  increased membrane hyperpolarization of "commonsense" neurons. 
C)  more action potentials in your "commonsense" neurons. 
D)  more EPSPs in your "commonsense" neurons. 
E)  fewer IPSPs in your "commonsense" neurons.

Question 14

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 membrane 
B)  axon hillock 
C)  dendritic membrane 
D)  presynaptic membrane

Question 15

The botulinum toxin inhibits the synaptic release of

Accepted Answer

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

Question 16

ATP hydrolysis directly powers the movement of

Accepted Answer

A)  K+ out of cells. 
B)  Na+ out of cells. 
C)  Na+ into cells. 
D)  Ca2+ into cells. 
E)  Cl- into cells.

Question 17

Self-propagation and refractory periods are typical of

Accepted Answer

A)  action potentials. 
B)  graded hyperpolarizations. 
C)  excitatory postsynaptic potentials. 
D)  inhibitory postsynaptic potentials. 
E)  resting potentials.

Question 18

An amino acid that operates at inhibitory synapses in the brain is

Accepted Answer

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

Question 19

The following steps refer to various stages in transmission at a chemical synapse.
1) Neurotransmitters bind with receptors associated with the postsynaptic membrane.
2) Calcium ions rush into the neuron's cytoplasm.
3) An action potential depolarizes the membrane of the axon terminal.
4) The ligand-gated ion channels open.
5) The synaptic vesicles release neurotransmitters into the synaptic cleft.
Which sequence of events is correct?

Accepted Answer

A)  1 → 2 → 3 → 4 → 5 
B)  2 → 3 → 5 → 4 → 1 
C)  3 → 2 → 5 → 1 → 4 
D)  4 → 3 → 1 → 2 → 5 
E)  5 → 1 → 2 → 4 → 3

Question 20

The operation of the sodium-potassium "pump" moves

Accepted Answer

A)  sodium and potassium ions into the cell. 
B)  sodium and potassium ions out of the cell. 
C)  sodium ions into the cell and potassium ions out of the cell. 
D)  sodium ions out of the cell and potassium ions into the cell. 
E)  sodium and potassium ions into the mitochondria.

Exam 37: Neurons, Synapses, and Signaling

The nucleus and most of the organelles in a neuron are located in the

In a simple synapse, neurotransmitter chemicals are released by

A graded hyperpolarization of a membrane can be induced by

Receptors for neurotransmitters are of primary functional importance in assuring one-way synaptic transmission because they are mostly found on the

A common feature of action potentials is that they

The point of connection between two communicating neurons is called the

When several excitatory postsynaptic potentials (EPSPs) arrive at the axon hillock from different dendritic locations and then depolarize the postsynaptic cell to threshold for an action potential, this is an example of

A chemical that affects neuronal function but is not stored in presynaptic vesicles is

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

In Figure 37.1, the minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

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

The botulinum toxin inhibits the synaptic release of

ATP hydrolysis directly powers the movement of

Self-propagation and refractory periods are typical of

An amino acid that operates at inhibitory synapses in the brain is

The operation of the sodium-potassium "pump" moves