Question 1

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.

Question 2

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 3

In a typical mammalian cell, if the [K⁺]ₒᵤtsᵢdₑ = 5mM and [K⁺]ᵢnsᵢdₑ = 140mM, what is the Nernst potential?

Accepted Answer

A) +62mV 
B) -90mV 
C) +90mV 
D) -62mV 
E) -1.4mV 
A) +62mV 
B) -90mV 
C) +90mV 
D) -62mV 
E) -1.4mV

Question 4

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 5

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

Question 6

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 7

Assume that excessive consumption of ethanol increases the influx of negative chloride ions into "common sense" 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 "common sense" neurons. 
B) decreased membrane depolarization of "common sense" neurons. 
C) more action potentials in your "common sense" neurons. 
D) more EPSPs in your "common sense" neurons. 
E) fewer IPSPs in your "common sense" neurons. 
A) increased membrane depolarization of "common sense" neurons. 
B) decreased membrane depolarization of "common sense" neurons. 
C) more action potentials in your "common sense" neurons. 
D) more EPSPs in your "common sense" neurons. 
E) fewer IPSPs in your "common sense" neurons.

Question 8

The botulinum toxin reduces the synaptic release 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 9

Use the following information to answer the next few questions.
The baseball career of Lou Gehrig, a first baseman for the New York Yankees, ended once he became afflicted with amyotrophic lateral sclerosis (ALS). This disease causes the degeneration of motor neurons in the CNS, leading to rapidly progressive weakness, muscle spasticity, and atrophy. Research into the disease has shown that individuals with ALS have higher levels of the neurotransmitter glutamate in their serum and spinal fluid when compared to normal individuals.
-Temporal summation always involves

Accepted Answer

A) both inhibitory and excitatory inputs. 
B) synapses at more than one site. 
C) inputs that are not simultaneous. 
D) electrical synapses. 
E) multiple inputs at a single synapse. 
A) both inhibitory and excitatory inputs. 
B) synapses at more than one site. 
C) inputs that are not simultaneous. 
D) electrical synapses. 
E) multiple inputs at a single synapse.

Question 10

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

Accepted Answer

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

Question 11

Botulinum toxin inhibits the presynaptic release of acetylcholine. If inhibition occurs at a neuromuscular junction, then

Accepted Answer

A) the synaptic cleft will close. 
B) muscle contraction will cease. 
C) the post-synaptic cell will die. 
D) muscles will spasm. 
E) receptor ion channels will remain open. 
A) the synaptic cleft will close. 
B) muscle contraction will cease. 
C) the post-synaptic cell will die. 
D) muscles will spasm. 
E) receptor ion channels will remain open.

Question 12

Most of the neurons in the human brain are

Accepted Answer

A) sensory neurons. 
B) motor neurons. 
C) interneurons. 
D) auditory neurons. 
E) peripheral neurons. 
A) sensory neurons. 
B) motor neurons. 
C) interneurons. 
D) auditory neurons. 
E) peripheral neurons.

Question 13

In a simple synapse, neurotransmitter chemicals are received by

Accepted Answer

A) the dendritic membrane. 
B) the presynaptic membrane. 
C) axon hillocks. 
D) cell bodies. 
E) ducts on the smooth endoplasmic reticulum. 
A) the dendritic membrane. 
B) the presynaptic membrane. 
C) axon hillocks. 
D) cell bodies. 
E) ducts on the smooth endoplasmic reticulum.

Question 14

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 15

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 16

For the following questions, refer to the graph of an action potential.
  
-The cell is not hyperpolarized; however, repolarization is in progress, as the sodium channels are closing or closed, and many potassium channels have opened 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 17

For the following questions, refer to the graph of an action potential.
  
-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. 
A) A. 
B) B. 
C) C. 
D) D. 
E) E.

Question 18

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 19

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 in moving from the dendritic region to the axon terminal. 
C) 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 in moving from the dendritic region to the axon terminal. 
C) 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 20

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, using an electronic probe, 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.

Exam 48: Neurons, Synapses, and Signalling

The point of connection between two communicating neurons is called

In a typical mammalian cell, if the [K⁺]ₒᵤtsᵢdₑ = 5mM and [K⁺]ᵢnsᵢdₑ = 140mM, what is the Nernst potential?

An example of the action of metabotropic receptors occurs when

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

ATP hydrolysis directly powers the movement of

The botulinum toxin reduces the synaptic release of

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

Botulinum toxin inhibits the presynaptic release of acetylcholine. If inhibition occurs at a neuromuscular junction, then

Most of the neurons in the human brain are

In a simple synapse, neurotransmitter chemicals are received by

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

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

For the following questions, refer to the graph of an action potential. -The cell is not hyperpolarized; however, repolarization is in progress, as the sodium channels are closing or closed, and many potassium channels have opened at label

For the following questions, refer to the graph of an action potential. -The minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label

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

Saltatory conduction is a term applied to

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, using an electronic probe, then

Introduction: Evolution and Themes of Biology

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