Question 1

The parts of the graph indicated at points C, D, and E represent
A)the refractory period.
B)repolarization.
C)sodium channel activity.
D)depolarization.
E)hyperpolarization.

Accepted Answer

Points C, D, and E on a graph of an action potential typically represent the repolarization phase, where the membrane potential returns to a negative value after the peak of the action potential.

Question 2

The somatic nervous system controls
A)smooth muscle.
B)cardiac muscle.
C)some glands.
D)skeletal muscles.
E)the brain and spinal cord.

Accepted Answer

The somatic nervous system is responsible for voluntary control of skeletal muscles.

Question 3

The resting potential of a particular nerve cell is - 66 mV. Depolarization of the membrane will shift the membrane potential toward
A)0 mV.
B)- 66 mV.
C)- 90 mV.
D)There will be no change.
E)There is not enough information to tell.

Accepted Answer

Depolarization refers to the process by which the membrane potential becomes less negative (more positive) than the resting potential. Therefore, it will shift towards 0 mV.

Question 4

You are examining a recently captured organism from another planet and are currently trying to deduce the types of neurotransmitters associated with the propagation of nerve impulses. You discover a very interesting neurotransmitter and find that, in spite of being alien, it is a derivative of the amino acid tyrosine. As a result, this novel neurotransmitter has to be classified as a(n)
A)neuropeptide.
B)serotinin analog.
C)GABA analog.
D)catecholamine.
E)acetylcholine analog.

Accepted Answer

Catecholamines are neurotransmitters derived from the amino acid tyrosine, such as dopamine, norepinephrine, and epinephrine.

Question 5

The stimulus for secretion of neurotransmitters into the synaptic cleft is an increase in
A)neurotransmitter levels.
B)chloride levels.
C)calcium levels.
D)potassium levels.
E)sodium levels.

Accepted Answer

An increase in calcium levels triggers the release of neurotransmitters into the synaptic cleft by causing synaptic vesicles to fuse with the presynaptic membrane.

Question 6

As a result of the way nerve impulses are propagated, they are unidirectional. Which of the following does NOT contribute to this phenomenon?
A)Unidirectional sodium and potassium channels open only toward the axon of the nerve cell.
B)Presynaptic neurotransmitters and postsynaptic receptors are separated.
C)Sensory processes are oriented in such a manner that the information is targeted to the dendrites of the nerve cell.
D)The time interval encompassed by the refractory period does NOT allow the impulse to travel in reverse.
E)none of the above

Accepted Answer

The unidirectional nature of nerve impulses is not due to unidirectional sodium and potassium channels, as these channels open in response to voltage changes and are not inherently directional. The other options contribute to the unidirectional propagation of nerve impulses.

Question 7

Of all of the ions associated with generating the resting membrane potential, the permeability of the membrane to _ is the most important.
A)potassium ions
B)sodium ions
C)chloride ions
D)all of the above
E)none of the above

Accepted Answer

The resting membrane potential is primarily determined by the permeability of the membrane to potassium ions, as they have the highest permeability compared to other ions, allowing them to move more freely across the membrane and influence the potential.

Question 8

The portion of the nervous system that is associated with the control of involuntary activities is the
A)autonomic nervous system.
B)automatic nervous system.
C)peripheral nervous system.
D)central nervous system.
E)somatic nervous system.

Accepted Answer

The autonomic nervous system is responsible for regulating involuntary body functions such as heartbeat, blood flow, breathing, and digestion.

Question 9

Which equation best describes the relationship between ion gradient and equilibrium membrane potential for that ion?
A)Nernst
B)Steady- state
C)Katz
D)Goldman
E)Hodgkin

Accepted Answer

The Nernst equation calculates the equilibrium potential for a specific ion based on its concentration gradient across the membrane.

Question 10

You treat an organism with a drug that inhibits calcium permeability in nerve cells specifically. As a result, you expect to see
A)no depolarization of membranes.
B)failure to achieve the threshold necessary to stimulate a signal.
C)no repolarization of membranes.
D)no postsynaptic receptors.
E)presynaptic neurotransmitter release.

Accepted Answer

Inhibition of calcium permeability in nerve cells would prevent the influx of calcium ions necessary for the release of neurotransmitters from presynaptic terminals, affecting neurotransmitter release.

Question 11

The glial cell associated with phagocytosis to fight infection and remove debris are the
A)Schwann cells.
B)oligodendrocytes.
C)microglia.
D)astrocytes.
E)myelin sheath.

Accepted Answer

Microglia are the glial cells responsible for phagocytosis, helping to fight infection and remove debris in the central nervous system.

Question 12

Multiple sclerosis is a result of
A)excess amounts of myelin on nerve cells.
B)an immune system attack on nerve fibers.
C)the absence of myelin on nerve cells.
D)blocking the nodes on Ranvier.
E)having excess acetylcholine receptors.

Accepted Answer

Multiple sclerosis is an autoimmune disease where the immune system mistakenly attacks the myelin sheath covering nerve fibers, leading to communication problems between the brain and the rest of the body.

Question 13

Catecholamines are synthesized by the
A)adrenal gland.
B)liver.
C)anterior pituitary gland.
D)skeletal muscle.
E)hypothalamus.

Accepted Answer

Catecholamines, such as adrenaline and noradrenaline, are synthesized by the adrenal glands, specifically in the adrenal medulla.

Question 14

An example of an inhibitory neurotransmitter is
A)dopamine.
B)GABA.
C)insulin.
D)epinephrine.
E)acetylcholine.

Accepted Answer

GABA is an inhibitory neurotransmitter that helps to reduce neuronal excitability and calm the nervous system.

Question 15

The technique that allows one to record ion currents passing through individual channels is known as
A)ionophores.
B)ligand- gating.
C)patch- clamping.
D)voltage- gating.
E)ion sensors.

Accepted Answer

Patch-clamping is a technique used to record ion currents through individual ion channels by isolating a small patch of membrane.

Question 16

Which of the following statements if FALSE regarding the nicotinic acetylcholine receptor?
A)Biochemical purification was aided by cobratoxin.
B)It binds one molecule of acetylcholine for activity.
C)The open channel allows an influx of sodium ions.
D)It is comprised of four large subunits.
E)The actions of acetylcholine can be mimicked by nicotine.

Accepted Answer

The nicotinic acetylcholine receptor requires the binding of two molecules of acetylcholine for activation, not just one.

Question 17

Name for the phase at the end of an action potential when the membrane potential becomes more negative than it is at rest is the _ phase.
A)hyperpolarizing
B)refractory
C)repolarizing
D)threshold
E)depolarizing

Accepted Answer

The hyperpolarizing phase, also known as the afterhyperpolarization phase, occurs when the membrane potential becomes more negative than the resting potential following an action potential.

Question 18

The maximum membrane potential that an ion gradient can produce is the
A)resting potential.
B)actualized potential.
C)equilibrium potential.
D)membrane potential.
E)action potential.

Accepted Answer

The equilibrium potential is the maximum membrane potential that can be produced by an ion gradient, as it represents the balance point where the net flow of the ion across the membrane is zero.

Question 19

Based on your knowledge of nerve transmission, this movement of ions will
A)stimulate a change in a postsynaptic membrane, if three channel events are combined.
B)not stimulate a change in the postsynaptic membrane.
C)stimulate a change in a postsynaptic membrane, if 50 channel events are combined.
D)generate a current resulting in membrane depolarization.
E)stimulate a change in a postsynaptic membrane.

Accepted Answer

The answer of Based on your knowledge of nerve transmission,...

Question 20

The sweetener aspartame is a known excitotoxin. With regard to nerve cells, ingestion of this substance results in chronic nerve stimulation. With your knowledge of action potentials, this toxin must
A)stimulate continual impulses at the cell body.
B)block the synaptic cleft.
C)stimulate continual impulses at the dendrite.
D)bind the nodes of Ranvier.
E)stimulate continual impulses at the presynaptic receptors.

Accepted Answer

Aspartame, as an excitotoxin, causes chronic nerve stimulation by affecting the dendrites, which are responsible for receiving signals and initiating action potentials.

Quiz 13: Signal Transduction Mechanisms: I Electrical and Synaptic Signaling in Neurons

The parts of the graph indicated at points C, D, and E represent

The somatic nervous system controls

The resting potential of a particular nerve cell is - 66 mV. Depolarization of the membrane will shift the membrane potential toward

The stimulus for secretion of neurotransmitters into the synaptic cleft is an increase in

As a result of the way nerve impulses are propagated, they are unidirectional. Which of the following does NOT contribute to this phenomenon?

Of all of the ions associated with generating the resting membrane potential, the permeability of the membrane to _ is the most important.

The portion of the nervous system that is associated with the control of involuntary activities is the

Which equation best describes the relationship between ion gradient and equilibrium membrane potential for that ion?

You treat an organism with a drug that inhibits calcium permeability in nerve cells specifically. As a result, you expect to see

The glial cell associated with phagocytosis to fight infection and remove debris are the

Multiple sclerosis is a result of

Catecholamines are synthesized by the

An example of an inhibitory neurotransmitter is

The technique that allows one to record ion currents passing through individual channels is known as

Which of the following statements if FALSE regarding the nicotinic acetylcholine receptor?

Name for the phase at the end of an action potential when the membrane potential becomes more negative than it is at rest is the _ phase.

The maximum membrane potential that an ion gradient can produce is the

Based on your knowledge of nerve transmission, this movement of ions will

The sweetener aspartame is a known excitotoxin. With regard to nerve cells, ingestion of this substance results in chronic nerve stimulation. With your knowledge of action potentials, this toxin must