Question 1

Which is FALSE about the equilibrium potential of a given ion across a membrane?

Accepted Answer

A)  It is a function of the concentration of that ion on both sides of the membrane. 
B)  It is the potential at which there is no net movement of that ion across the membrane. 
C)  It is the potential difference across the membrane at which an electric force favoring movement of the ion in one direction is equal in magnitude and opposite in direction to the diffusion force provided by the concentration difference of the ion across the membrane. 
D)  A permeable ion will move in the direction that will tend to bring the membrane potential toward that ion's equilibrium potential. 
E)  An anion that is in higher concentration inside the cell than outside the cell will have a negative eqilibrium potential. 
A)  It is a function of the concentration of that ion on both sides of the membrane. 
B)  It is the potential at which there is no net movement of that ion across the membrane. 
C)  It is the potential difference across the membrane at which an electric force favoring movement of the ion in one direction is equal in magnitude and opposite in direction to the diffusion force provided by the concentration difference of the ion across the membrane. 
D)  A permeable ion will move in the direction that will tend to bring the membrane potential toward that ion's equilibrium potential. 
E)  An anion that is in higher concentration inside the cell than outside the cell will have a negative eqilibrium potential.

Question 2

Why are action potentials sometimes described as being "all-or-none" in character?

Accepted Answer

A)  The rate of propagation of an action potential down an axon is independent of stimulus strength. 
B)  They are associated with an absolute refractory period. 
C)  A supra-threshold stimulus is required to stimulate an action potential during the relative refractory period. 
D)  An action potential occurs whenever a suprathreshold stimulus occurs, and its amplitude does not vary with the size of a stimulus, as long as the membrane is not in the refractory period. 
E)  Action potentials are always the same size, even when ion gradients vary in size. 
A)  The rate of propagation of an action potential down an axon is independent of stimulus strength. 
B)  They are associated with an absolute refractory period. 
C)  A supra-threshold stimulus is required to stimulate an action potential during the relative refractory period. 
D)  An action potential occurs whenever a suprathreshold stimulus occurs, and its amplitude does not vary with the size of a stimulus, as long as the membrane is not in the refractory period. 
E)  Action potentials are always the same size, even when ion gradients vary in size.

Question 3

The ________________ is best described as "an interconnected group of brain structures including parts of the frontal lobe-cortex, temporal lobe, thalamus, and hypothalamus, that is associated with learning, emotional experience, and behavior?"

Accepted Answer

A)  diencephalon 
B)  cerebrum 
C)  limbic system 
D)  reticular formation 
E)  cerebellum 
A)  diencephalon 
B)  cerebrum 
C)  limbic system 
D)  reticular formation 
E)  cerebellum

Question 4

Which of the following is NOT known to be an important neurotransmitter in the CNS?

Accepted Answer

A)  Dopamine 
B)  Acetylcholine 
C)  Morphine 
D)  Glutamate 
E)  Substance P 
A)  Dopamine 
B)  Acetylcholine 
C)  Morphine 
D)  Glutamate 
E)  Substance P

Question 5

Synthesis of neuropeptides differs from that of other neurotransmitters because it:

Accepted Answer

A)  takes place in the axon terminals of neurons. 
B)  takes place in the cell bodies of neurons. 
C)  takes place on ribosomes in the postsynaptic cell's membrane. 
D)  uses amino acids as precursor molecules. 
E)  only takes place at synapses outside the central nervous system. 
A)  takes place in the axon terminals of neurons. 
B)  takes place in the cell bodies of neurons. 
C)  takes place on ribosomes in the postsynaptic cell's membrane. 
D)  uses amino acids as precursor molecules. 
E)  only takes place at synapses outside the central nervous system.

Question 6

Which must happen in order for an action potential to begin?

Accepted Answer

A)  The membrane potential must be at the Na+ equilibrium potential. 
B)  Na+ influx must exceed K+ efflux. 
C)  The membrane must be out of the relative refractory period. 
D)  Na+ channels must all be inactivated. 
E)  Multiple inhibitory postsynaptic potentials (IPSPs) must summate. 
A)  The membrane potential must be at the Na+ equilibrium potential. 
B)  Na+ influx must exceed K+ efflux. 
C)  The membrane must be out of the relative refractory period. 
D)  Na+ channels must all be inactivated. 
E)  Multiple inhibitory postsynaptic potentials (IPSPs) must summate.

Question 7

The cerebrum consists only of gray matter.

Accepted Answer

A) True 
 B)False

Question 8

The efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following statements about the refractory period of a membrane is TRUE?

Accepted Answer

A)  The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that is undergoing an action potential, no matter how great the strength of the stimulus. 
B)  The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential if a stronger than normal stimulus is applied. 
C)  The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential. 
D)  The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials. 
E)  All of the above choices are correct. 
A)  The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that is undergoing an action potential, no matter how great the strength of the stimulus. 
B)  The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential if a stronger than normal stimulus is applied. 
C)  The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential. 
D)  The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials. 
E)  All of the above choices are correct.

Question 10

Which of the following statements concerning the rate of action potential propagation is TRUE?

Accepted Answer

A)  It is faster in small-diameter axons than in large-diameter axons. 
B)  It is faster for a strong stimulus than for a weak one. 
C)  It is faster in myelinated axons than in nonmyelinated axons. 
D)  It is faster in the dendrites than in the axon. 
E)  It occurs at the same rate in all axons, regardless of their diameter. 
A)  It is faster in small-diameter axons than in large-diameter axons. 
B)  It is faster for a strong stimulus than for a weak one. 
C)  It is faster in myelinated axons than in nonmyelinated axons. 
D)  It is faster in the dendrites than in the axon. 
E)  It occurs at the same rate in all axons, regardless of their diameter.

Question 11

The absolute refractory period of an excitable membrane roughly corresponds to the period when sodium channels are opening and inactivated.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following statements regarding action potentials generated in a neuronal membrane is FALSE?

Accepted Answer

A)  Action potentials travel decrementally down the membrane. 
B)  An action potential generates a new action potential in an adjacent area of membrane. 
C)  An action potential generates a local current that depolarizes adjacent membrane to threshold potential. 
D)  Action potentials are usually initiated at the initial segment of a neuron. 
E)  An action potential generated by a threshold stimulus is the same size as one generated by a supra-threshold stimulus. 
A)  Action potentials travel decrementally down the membrane. 
B)  An action potential generates a new action potential in an adjacent area of membrane. 
C)  An action potential generates a local current that depolarizes adjacent membrane to threshold potential. 
D)  Action potentials are usually initiated at the initial segment of a neuron. 
E)  An action potential generated by a threshold stimulus is the same size as one generated by a supra-threshold stimulus.

Question 13

The lipid portion of a cell's plasma membrane constitutes a barrier to current.

Accepted Answer

A) True 
 B)False

Question 14

The difference in electrical charge between two points:

Accepted Answer

A)  is called the potential difference between those points. 
B)  is called the diffusion potential between those points. 
C)  is called the current, and is expressed in the units of millimoles. 
D)  is the same for all ions. 
A)  is called the potential difference between those points. 
B)  is called the diffusion potential between those points. 
C)  is called the current, and is expressed in the units of millimoles. 
D)  is the same for all ions.

Question 15

Which of the following statements concerning the permeability of a typical neuron membrane at rest is TRUE?

Accepted Answer

A)  The permeability to Na+ is much greater than the permeability to K+. 
B)  All of the K+ channels in the membrane are open. 
C)  The voltage-gated Na+ channels are in the inactivated state. 
D)  Most of the voltage-gated Na+ channels are in the closed state. 
E)  There is equal permeability to Na+ and K+. 
A)  The permeability to Na+ is much greater than the permeability to K+. 
B)  All of the K+ channels in the membrane are open. 
C)  The voltage-gated Na+ channels are in the inactivated state. 
D)  Most of the voltage-gated Na+ channels are in the closed state. 
E)  There is equal permeability to Na+ and K+.

Question 16

A myelinated axon is shielded from direct contact with the extracellular fluid all along its length.

Accepted Answer

A) True 
 B)False

Question 17

Which is most directly responsible for the falling (repolarizing) phase of the action potential?

Accepted Answer

A)  Voltage-gated Na+ channels are opened. 
B)  The Na+, K+ pump restores the ions to their original locations inside and outside of the cell. 
C)  The permeability to Na+ increases greatly. 
D)  ATPase destroys the energy supply that was maintaining the action potential at its peak. 
E)  The permeability to K+ increases greatly while that to Na+ decreases. 
A)  Voltage-gated Na+ channels are opened. 
B)  The Na+, K+ pump restores the ions to their original locations inside and outside of the cell. 
C)  The permeability to Na+ increases greatly. 
D)  ATPase destroys the energy supply that was maintaining the action potential at its peak. 
E)  The permeability to K+ increases greatly while that to Na+ decreases.

Question 18

Which of the following statements regarding neurotransmitters is TRUE?

Accepted Answer

A)  Acetylcholine is broken down by enzymes present on postsynaptic cell membranes. 
B)  Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane. 
C)  Catecholamines are the most abundant neurotransmitters in the central nervous system. 
D)  Opiate drugs, such as morphine, are antagonists of a class of neurotransmitters called endorphins. 
E)  Gamma-aminobutyric acid (GAB
A)  is a major excitatory transmitter in the central nervous system. 
A)  Acetylcholine is broken down by enzymes present on postsynaptic cell membranes. 
B)  Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane. 
C)  Catecholamines are the most abundant neurotransmitters in the central nervous system. 
D)  Opiate drugs, such as morphine, are antagonists of a class of neurotransmitters called endorphins. 
E)  Gamma-aminobutyric acid (GAB
A)  is a major excitatory transmitter in the central nervous system.

Question 19

Which of the following is NOT true about axon transport?

Accepted Answer

A)  It refers to the passage of materials from the cell body of a neuron to the axon terminals. 
B)  It refers to the passage of materials from axon terminals to the cell body of a neuron. 
C)  It refers to the transport of materials from the inside to the outside across the axonal membrane. 
D)  It is especially important for maintaining the integrity of neurons with long axons. 
A)  It refers to the passage of materials from the cell body of a neuron to the axon terminals. 
B)  It refers to the passage of materials from axon terminals to the cell body of a neuron. 
C)  It refers to the transport of materials from the inside to the outside across the axonal membrane. 
D)  It is especially important for maintaining the integrity of neurons with long axons.

Question 20

The portion of the peripheral nervous system that is composed of nerve fibers that innervate skeletal muscle is called the:

Accepted Answer

A)  afferent nervous system. 
B)  sympathetic nervous system. 
C)  parasympathetic nervous system. 
D)  somatic motor nervous system. 
E)  autonomic nervous system. 
A)  afferent nervous system. 
B)  sympathetic nervous system. 
C)  parasympathetic nervous system. 
D)  somatic motor nervous system. 
E)  autonomic nervous system.

Which is FALSE about the equilibrium potential of a given ion across a membrane?

Why are action potentials sometimes described as being "all-or-none" in character?

The ________________ is best described as "an interconnected group of brain structures including parts of the frontal lobe-cortex, temporal lobe, thalamus, and hypothalamus, that is associated with learning, emotional experience, and behavior?"

Which of the following is NOT known to be an important neurotransmitter in the CNS?

Synthesis of neuropeptides differs from that of other neurotransmitters because it:

Which must happen in order for an action potential to begin?

The cerebrum consists only of gray matter.

The efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system.

Which of the following statements about the refractory period of a membrane is TRUE?

Which of the following statements concerning the rate of action potential propagation is TRUE?

The absolute refractory period of an excitable membrane roughly corresponds to the period when sodium channels are opening and inactivated.

Which of the following statements regarding action potentials generated in a neuronal membrane is FALSE?

The lipid portion of a cell's plasma membrane constitutes a barrier to current.

The difference in electrical charge between two points:

Which of the following statements concerning the permeability of a typical neuron membrane at rest is TRUE?

A myelinated axon is shielded from direct contact with the extracellular fluid all along its length.

Which is most directly responsible for the falling (repolarizing) phase of the action potential?

Which of the following statements regarding neurotransmitters is TRUE?

Which of the following is NOT true about axon transport?

The portion of the peripheral nervous system that is composed of nerve fibers that innervate skeletal muscle is called the:

Homeostasis: a Framework for Human Physiology

Chemical Composition of the Body and Its Relation to Physiology

Cellular Structure, Proteins, and Metabolic Pathways

Movement of Molecules Across Cell Membranes

Cell Signaling in Physiology

Sensory Physiology

Consciousness, the Brain, and Behavior

Muscle

Control of Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

The Digestion and Absorption of Food

Regulation of Organic Metabolism and Energy Balance

Reproduction

The Immune System

Filters

Exam 6: Neuronal Signaling and the Structure of the Nervous System

Which is FALSE about the equilibrium potential of a given ion across a membrane?

Why are action potentials sometimes described as being "all-or-none" in character?

The ________________ is best described as "an interconnected group of brain structures including parts of the frontal lobe-cortex, temporal lobe, thalamus, and hypothalamus, that is associated with learning, emotional experience, and behavior?"

Which of the following is NOT known to be an important neurotransmitter in the CNS?

Synthesis of neuropeptides differs from that of other neurotransmitters because it:

Which must happen in order for an action potential to begin?

The cerebrum consists only of gray matter.

The efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system.

Which of the following statements about the refractory period of a membrane is TRUE?

Which of the following statements concerning the rate of action potential propagation is TRUE?

The absolute refractory period of an excitable membrane roughly corresponds to the period when sodium channels are opening and inactivated.

Which of the following statements regarding action potentials generated in a neuronal membrane is FALSE?

The lipid portion of a cell's plasma membrane constitutes a barrier to current.

The difference in electrical charge between two points:

Which of the following statements concerning the permeability of a typical neuron membrane at rest is TRUE?

A myelinated axon is shielded from direct contact with the extracellular fluid all along its length.

Which is most directly responsible for the falling (repolarizing) phase of the action potential?

Which of the following statements regarding neurotransmitters is TRUE?

Which of the following is NOT true about axon transport?

The portion of the peripheral nervous system that is composed of nerve fibers that innervate skeletal muscle is called the:

Homeostasis: a Framework for Human Physiology

Chemical Composition of the Body and Its Relation to Physiology

Cellular Structure, Proteins, and Metabolic Pathways

Movement of Molecules Across Cell Membranes

Cell Signaling in Physiology

Sensory Physiology

Consciousness, the Brain, and Behavior

Muscle

Control of Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

The Digestion and Absorption of Food

Regulation of Organic Metabolism and Energy Balance

Reproduction

The Immune System

Filters