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

Question 1

According to the equation expressed as Ohm's law,which of these would cause the greatest increase in current?

A)Doubling both voltage and resistance
B)Reducing both voltage and resistance by half
C)Doubling voltage and reducing resistance by half
D)Reducing voltage by half and doubling resistance
E)Quadrupling both voltage and resistance

Answer 1

C

Question 2

The membrane potential of most neurons at rest is

A)equal to the equilibrium potential for potassium.
B)equal to the equilibrium potential for sodium.
C)slightly more negative than the equilibrium potential of potassium ion.
D)more positive than the equilibrium potential for potassium.
E)more positive than the equilibrium potential for sodium.

Answer 2

D

Question 3

Which of these would occur if the concentration of ATP were depleted in a typical nerve cell?

A)Resting membrane potential would become more negative.
B)Resting membrane potential would become less negative.
C)The concentration gradient for Na⁺ would remain the same.
D)The resting membrane potential would eventually become positive inside with respect to outside.
E)There would be no change in the resting membrane potential.

Answer 3

B

Question 4

Compartments A and B are separated by a membrane that is permeable to K⁺ but not to Na⁺ or Cl⁻.At time zero,a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B.Which would be true once equilibrium is reached?

A)The concentration of Na⁺ in A will be higher than it was at time zero.
B)Diffusion of K⁺ from A to B will be greater than the diffusion of K⁺ from B to A.
C)There will be a potential difference across the membrane,with side B negative relative to side A.
D)The electrical potential difference and diffusion potential due to the concentration gradient for K⁺ will be equal in magnitude and opposite in direction.
E)The concentration of Cl⁻ will be higher in B than it was at time zero.

Question 5

Which is TRUE about typical,resting neurons?

A)The plasma membrane is most permeable to sodium ions.
B)The concentration of sodium ion is greater inside the cell than outside.
C)The permeability of the plasma membrane to potassium ions is much greater than its permeability to sodium ions.
D)The plasma membrane is completely impermeable to sodium ions.
E)The plasma membrane is completely impermeable to potassium ions.

Question 6

Which of the following is NOT true about axon transport?

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 7

Which is FALSE about neurons?

A)A given neuron can be either a presynaptic neuron or a postsynaptic neuron.
B)An individual  neuron can receive information from multiple other neurons.
C)An individual neuron can transmit information to multiple other neurons.
D)A neuron can simultaneously release more than one type of neurotransmitter.
E)A neuron receives information on its axons and delivers it to other neurons through its dendrites.

Question 8

Which is TRUE about the Na⁺,K⁺ ATPase pump in neurons?

A)It generates a small electrical potential such that the inside is made negative with respect to the outside.
B)It maintains a concentration gradient for K⁺ such that diffusion forces favor movement of K⁺ into the cell.
C)It maintains an electrical gradient at the equilibrium potential of K⁺.
D)It transports equal numbers of sodium and potassium ions with each pump cycle.
E)It pumps 3 Na⁺ ions into the cell for every 2 K⁺ ions it pumps out.

Question 9

If there was an increased concentration of K⁺ outside of the neuron,which would be TRUE?

A)Neurons would spontaneously depolarize.
B)Neurons would spontaneously hyperpolarize.
C)The potassium equilibrium potential of nerve cells would become more negative. 
D)The sodium equilibrium potential would become less positive.
E)During an action potential,the neuron would repolarize slowly or stay depolarized.

Question 10

Which is NOT an example of a graded potential?

A)A receptor potential in a sensory receptor cell
B)A depolarizing excitatory postsynaptic potential (EPSP)
C)A hyperpolarizing inhibitory postsynaptic potential (IPSP)
D)A depolarizing pacemaker potential
E)A depolarizing action potential

Question 11

The difference in electrical charge between two points

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 12

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

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 13

Some viruses can hide from the immune system by retrograde transport from axonal terminals in the skin to the cell body of a neuron.  Which of the following might be an effective preventative therapy?

A)A kinesin inhibitor
B)A dynein inhibitor
C)Actin polymerization inhibitor
D)Myosin inhibitor
E)None of these would prevent this type of infection

Question 14

Which of the following is NOT true of glial cells?

A)They form the myelin for axons.
B)They are outnumbered 10 to 1 by neurons in the nervous system.
C)They deliver fuel molecules to neurons and remove the waste products of metabolism.
D)They are important for the growth and development of the nervous system.
E)They regulate the composition of the extracellular fluid in the CNS.

Question 15

Two neighboring neurons are at rest.  Neuron A has a resting membrane potential of -80mV,Neuron B has a resting membrane potential of -70mV. Which is likely to be TRUE?

A)Neuron A has more K⁺ channels open than Neuron B.
B)Neuron B has more K⁺ channels open than Neuron A.
C)Neuron A has more Na⁺ channels open than Neuron B.
D)Neuron B has more Na⁺ channels open than Neuron A.
E)None of the answer choices are correct.

Question 16

You are studying a cross-sectional tissue slice of a nerve using a transmission electron microscope.  You find an area where there appears to be a small amount of cytoplasm surrounded by about 100 layers of stacked cell membranes.You conclude that you have found

A)a neuron cell body.
B)a synapse.
C)an unmyelinated axon.
D)a myelinated axon.

Question 17

Which is TRUE about the resting membrane potential?

A)It requires very few ions to be distributed unevenly.
B)It has the same value in all cells.
C)It is oriented so that the cell's interior is positive with respect to the extracellular fluid.
D)Only nerve and muscle cells have a potential difference across the membrane at rest.
E)It is not altered by changing concentration gradients of permeating ions.

Question 18

An action potential in a neuronal membrane differs from a graded potential in that

A)an action potential requires the opening of Ca²⁺ channels,whereas a graded potential does not.
B)an action potential is propagated without decrement,whereas a graded potential decrements with distance.
C)an action potential has a threshold,whereas a graded potential is an all-or-none phenomenon.
D)movement of Na⁺ and K⁺ across cell membranes mediate action potentials,while graded potentials do not involve movement of Na⁺ and K⁺.
E)action potentials vary in size with the size of a stimulus,while graded potentials do not.

Question 19

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

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 equilibrium potential.

Question 20

Which of the following is TRUE about the concentration gradient of Na⁺ in a neuron at rest?

A)It favors its movement into the cell at the resting membrane potential.
B)It favors its movement out of the cell at the resting membrane potential.
C)It is equal and opposite to the electrical potential acting on Na⁺ at the resting membrane potential.
D)It is in the same direction as the diffusion potential due to the concentration gradient for K⁺.
E)It favors movement of Na⁺ in the opposite direction as the electrical potential acting on Na⁺ at the resting membrane potential.

Question 21

If you block Ca²⁺ channels on an axon,which will not occur?

A)The depolarization phase of the action potential
B)The repolarization phase of the action potential
C)The exocytosis of neurotransmitter
D)The graded potential
E)All of these will not occur

Question 22

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

A)Action potentials travel in both directions along the axon.
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 axon hillock 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 23

An action potential does not re-stimulate the adjacent membrane that was previously depolarized because

A)stimulation is inhibited by the myelin sheath.
B)it is impossible for an action potential to be propagated along an axon toward the nerve cell body.
C)the resting membrane potential of the axon is too positive.
D)the resting membrane potential of the axon is too negative.
E)that area of the membrane is in the absolutely refractory period.

Question 24

Neuronal axons typically have abundant

A)voltage-gated channels for Na⁺ that open in response to depolarization.
B)voltage-gated channels for K⁺ that open in response to hyperpolarization.
C)ligand-gated channels for Na⁺.
D)ligand-gated channels for K⁺.
E)voltage-gated channels for Ca²⁺.

Question 25

Two stimuli occur on the same neuron more than a minute apart.  The second stimulus is more than ten times greater than the first.  If we compare the two resulting action potentials,which is TRUE?

A)The second stimulus will lead to an action potential with higher amplitude.
B)The second stimulus will lead to an action potential with a longer duration.
C)The second stimulus will lead to an action potential with a longer hyperpolarization at the end.
D)The amplitude of the two action potentials will be the same.
E)The amplitude and duration of the second action potential will be greater than the first.

Question 26

Which describes the response of the voltage-gated channels when an axon is stimulated to threshold?

A)K⁺ channels open before the Na⁺ channels.
B)Na⁺ channels are activated and then inactivated.
C)K⁺ channels open at the same time as the Na⁺ channels.
D)K⁺ channels are opened when Na⁺ binds to the channel.
E)K⁺ influx causes Na⁺ channels to inactivate.

Question 27

How is the strength of a stimulus encoded by neurons?

A)By the size of action potentials
B)By the frequency of action potentials
C)By the duration of action potentials
D)By whether the action potential peak is positive or negative

Question 28

Which of the following statements concerning the properties of action potentials is TRUE?

A)The rate of propagation of an action potential down an axon is independent of stimulus strength.
B)Action potentials can undergo summation.
C)A supra-threshold stimulus can stimulate an action potential during the absolute refractory period.
D)Action potentials generally propagate from the axon terminal toward the axon hillock.
E)Increasing the size of a stimulus will increase the amplitude of an action potential.

Question 29

The regions of myelinated axon membrane that have the highest permeability to ions are the

A)ganglia.
B)nodes of Ranvier.
C)synaptic membranes.
D)glial cells.
E)pia mater.

Question 30

Using a micropipette,a neuroscientist injects an axon with enough Na⁺ ions to move the membrane potential +25mV (from resting).What happens next?

A)The membrane potential will be at the Na⁺ equilibrium potential.
B)Voltage-gated Na⁺ will be triggered to open.
C)The neuron membrane will be hyperpolarized.
D)Na⁺ channels will all be inactivated.
E)None of the answer choices are correct.

Question 31

Inside a neuron,calcium binding sites are likely found on

A)smooth endoplasmic reticulum.
B)kinesin proteins.
C)proteins associated with synaptic vesicles.
D)dyenin proteins.
E)lysosomal proteins.

Question 32

Visual signals travel on myelinated axons.While most pain signals travel on unmyelinated axons.  If you get a paper cut,will you see the cut happen or feel the pain first?

A)Both sensations will occur at the same time.
B)You will feel the pain sensation before the visual sensation.
C)You will experience the visual sensation before the pain sensation.
D)It depends on the magnitude of the pain sensation,it may reach the brain first or second.

Question 33

During the rising (depolarizing)phase of a neuronal action potential,

A)PK₊ becomes much greater than PNₐ₊.
B)PNₐ₊ becomes much greater than PK₊.
C)PK₊ is the same as PNₐ₊.
D)Na⁺ efflux (flow out of the cell)occurs.
E)K⁺ flows rapidly into the cell.

Question 34

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

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 answer choices are correct.

Question 35

Which is TRUE about neuronal membrane electrical and concentration gradients at the peak of the action potential?

A)The electrical gradient is in a direction that would tend to move K⁺ out of the cell.
B)The concentration gradient for K⁺ is in a direction that would tend to move it into the cell.
C)The concentration gradient for K⁺ greatly increases compared to at rest.
D)The concentration gradient for Na⁺ is in a direction that would tend to move it out of the cell.
E)The electrical gradient for Na⁺ is in a direction that would tend to move it into the cell.

Question 36

The relative refractory period of an axon coincides with the period of

A)activation and inactivation of voltage-dependent Na⁺ channels.
B)Na⁺ permeability that is greater than that during the depolarization phase.
C)increased K⁺ flux into the cell.
D)increased K⁺ permeability of the cell.
E)Increased Na⁺ flux through K⁺ channels.

Question 37

Which is FALSE about interneurons?

A)They receive synaptic input from other neurons in the CNS.
B)They sum excitatory and inhibitory synaptic inputs.
C)They deliver synaptic input on other neurons. 
D)They make synapses on effector organs in the PNS.
E)They can transmit information between afferent neurons and efferent neurons. 

Question 38

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

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 39

Procaine (Novocain)is a drug that blocks voltage-gated Na⁺ channels.  When present,what would happen in a neuron?

A)Graded potentials are possible,but the neuron will not have the depolarizing phase of the action potential.
B)Neither graded potentials nor action potentials will occur.
C)Graded potentials are possible and the neuron will have the depolarizing phase of the action potential,but will be unable to repolarize.
D)No phase of the action potential will be affected.

Question 40

A threshold stimulus applied to an excitable membrane is one that is just sufficient to

A)trigger an excitatory postsynaptic potential.
B)cause a change in membrane potential.
C)trigger an action potential.
D)be conducted to the axon hillock.
E)depolarize a dendrite.

Question 41

A postsynaptic neuron has three presynaptic inputs-from neurons X,Y,and Z.Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously,the postsynaptic neuron depolarizes by 1 mV. When X and Z are stimulated simultaneously,however,there is no change in the membrane potential of the postsynaptic neuron.What is most likely true about presynaptic neurons Y and Z?

A)They are both excitatory.
B)They are both inhibitory.
C)Y is excitatory and Z is inhibitory.
D)Z is excitatory and Y is inhibitory.

Question 42

You are studying the role of a newly discovered neurotransmitter.  You find that there are receptors for this neurotransmitter on interneurons in the brain and that when it binds,it causes the opening of K⁺ channels.  What can we expect of the postsynaptic cells under influence of this neurostransmitter?

A)The postsynaptic cell will immediately undergo an action potential.
B)The postsynaptic cell will undergo an IPSP.
C)The postsynaptic cell will undergo an EPSP.
D)There will be no change to the membrane potential in the postsynaptic cell.

Question 43

Alzheimer's disease is thought to involve primarily

A)loss of neurons that secrete or respond to catecholamines.
B)loss of adrenergic neurons.
C)loss of cholinergic neurons.
D)loss of neurons that secrete or respond to dopamine.
E)tumors that produce excess serotonin.

Question 44

At an excitatory chemical synapse between two neurons

A)there is increased permeability of the postsynaptic cell to both Na⁺ and K⁺.
B)a small hyperpolarization of the postsynaptic membrane occurs when the synapse is activated.
C)an action potential in the presynaptic neuron always causes an action potential in the postsynaptic neuron.
D)excitation occurs because K⁺ enters the postsynaptic cell.
E)action potentials spread through gap junctions between cells.

Question 45

Neuron X makes inhibitory axon-axonal synaptic contact with neuron Y at the synapse of Y and neuron Z.Which will occur when action potentials are stimulated in neuron X?

A)Neuron Y will be inhibited from reaching the threshold to fire an action potential.
B)The release of neurotransmitter by neuron Y will be inhibited.
C)The synapse between neurons Y and Z will be changed from an excitatory synapse to an inhibitory one.
D)Neurons Y and Z will both be more likely to reach threshold and fire an action potential.
E)Neurons Y and Z will both be less likely to reach threshold and fire an action potential.

Question 46

Heroin causes similar,but much stronger effects to the nervous system as endogenous opioids.Heroin's mechanism of action might be that it acts as an:

A)agonist to serotonin receptors.
B)agonist to the endogenous opioid receptors.
C)agonist to glycine receptors.
D)agonist to epinephrine receptors.
E)Any of these are possible

Question 47

A postsynaptic neuron has an RMP of -70mV and a typical threshold of -55mV.  It has three presynaptic inputs-from neurons X,Y,and Z.Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously,the postsynaptic neuron depolarizes by 1 mV. If X fires 10 times and Y fires 10 times the result will be

A)a subthreshold summation.
B)presynaptic inhibition.
C)threshold is reached and an AP is fired.
D)many APs are fired.
E)the membrane depolarizes.

Question 48

Which best describes temporal summation?

A)A synapse is stimulated a second time before the effect of a first stimulus at the synapse has terminated.
B)It only refers to addition of EPSPs.
C)Two synapses on different regions of a cell are stimulated at the same time.
D)It always brings a postsynaptic cell to threshold.
E)The size of an EPSP depends on the size of the stimulus.

Question 49

Which of the following statements regarding neurotransmitters is TRUE?

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 (GABA)is a major excitatory transmitter in the central nervous system.

Question 50

Serotonin

A)acts as a neuromodulator.
B)is a catecholamine neurotransmitter.
C)is a neuropeptide.
D)has an inhibitory effect on pathways that are involved in the control of muscles.
E)has an excitatory effect on pathways that mediate sensations.

Question 51

Which of the following enzymes is important for the metabolism of catecholamines?

A)Tyrosine hydroxylase
B)Acetylcholinesterase
C)Superoxide dismutase
D)Trypsin
E)Adenylyl cyclase

Question 52

Acetylcholine is the main neurotransmitter released by

A)preganglionic sympathetic neurons and cells of the adrenal medulla.
B)cells of the adrenal medulla and postganglionic parasympathetic neurons.
C)motor neurons and postganglionic sympathetic neurons.
D)preganglionic sympathetic neurons and postganglionic sympathetic neurons.
E)preganglionic sympathetic neurons and motor neurons.

Question 53

Which is TRUE about the axon hillock of an axon?

A)Its membrane potential at threshold is more positive than that of the cell body and dendrites.
B)Its membrane potential at threshold is more negative than that of the cell body and dendrites.
C)Synapses far from the axon hillock are more effective in influencing whether an action potential will be generated in the axon than are synapses close to the axon hillock.
D)It is the region where neurotransmitter vesicles are docked and ready to be released by exocytosis.
E)It can only conduct graded potentials because it lacks voltage-gated Na⁺ channels.

Question 54

Nicotinic receptors are expressed on skeletal muscle cells.Which of the following would likely be a side-effect of the use of nicotine,an agonist for those receptors?

A)Muscle relaxation
B)Muscle cell twitches (contractions)
C)Muscle paralysis
D)Drowsiness
E)None of the answer choices are correct

Question 55

An EPSP

A)is a direct result of the opening of ligand-gated channels permeable to both Na⁺ and K⁺ ions.
B)is a direct result of the opening of voltage-gated channels permeable to both Na⁺ and K⁺ ions.
C)stabilizes the membrane to remain at its resting potential.
D)opens voltage-gated Ca²⁺ channels in the presynaptic membrane.
E)occurs when voltage-gated Cl⁻ channels open in a postsynaptic cell membrane.

Question 56

A presynaptic (axo-axonal)synapse

A)is a synapse between an axon terminal and a dendrite that can be either excitatory or inhibitory.
B)is a synapse between an axon terminal and another axon's terminal that can be either excitatory or inhibitory.
C)is any synapse onto a cell body,and they can be either stimulatory or inhibitory.
D)is a synapse between an axon terminal and a dendrite of the same cell,which is always inhibitory.
E)is a synapse between an axon terminal and another axon's terminal that is always inhibitory.

Question 57

Nicotine is

A)a cholinergic antagonist.
B)a beta-adrenergic agonist.
C)a cholinergic agonist.
D)an alpha-adrenergic antagonist.
E)a neurotransmitter.

Question 58

Which of the following statements about norepinephrine is FALSE?

A)Norepinephrine is a neurotransmitter.
B)Norepinephrine binds to adrenergic receptors.
C)Norepinephrine is a catecholamine. 
D)Dopamine is a precursor to norepinephrine.
E)Epinephrine is a precursor to norepinephrine.

Question 59

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

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

Question 60

Which of the following statements about EPSPs is FALSE?

A)They are produced by the opening of ligand-gated sodium channels.
B)They transmit signals over relatively short distances.
C)They depolarize postsynaptic cell membranes.
D)They are able to summate.
E)They are always the same amplitude.

Question 61

Which of the following kinds of neurons are NOT generally cholinergic?

A)Somatic motor neurons
B)Postganglionic sympathetic neurons
C)Postganglionic parasympathetic neurons
D)Preganglionic sympathetic neurons
E)Preganglionic parasympathetic neurons

Question 62

Which is one of the most abundant excitatory neurotransmitters in the CNS?

A)Glutamate
B)Dopamine
C)Norepinephrine
D)Gamma-aminobutyric acid (GABA)
E)Endorphin

Question 63

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

Question 64

Postganglionic neuron cell bodies of the autonomic nervous system have which category of neurotransmitter receptor?

A)Adrenergic receptors
B)Serotonin receptors
C)Muscarinic acetylcholine receptors
D)Nicotinic acetylcholine receptors
E)Dopamine receptors

Question 65

Which of the following is NOT characteristic of the sympathetic division of the autonomic nervous system?

A)Preganglionic neurons tend to be long,with the ganglion located in or near the effector target tissue(s).
B)Preganglionic neurons are short and synapse in ganglia located near the spinal cord.
C)Preganglionic neurons release acetylcholine at synapses with postganglionic neurons.
D)Postganglionic neurons release norepinephrine at their neuroeffector junctions.
E)Postganglionic neuron cell bodies are located in the collateral chain ganglia (sympathetic trunk).

Question 66

Excessive alcohol intake can cause difficulty maintaining posture and coordinating body movements.This is likely due to alcohol's effect stimulatory effect on GABA-releasing neurons in the

A)cerebellum.
B)diencephalon.
C)medulla oblongata.
D)eyes.
E)cerebrum.

Question 67

The central nervous system includes the

A)afferent nerves and spinal cord.
B)efferent nerves and spinal cord.
C)autonomic nervous system and the brain.
D)brain stem and the autonomic nervous system.
E)brain and spinal cord.

Question 68

A patient has been experiencing difficulty with homeostatic regulation.  An MRI scan reveals a brain tumor.Which brain region is the tumor likely in?

A)The thalamus
B)The hippocampus
C)The cerebrum
D)The cerebellum
E)The hypothalamus

Question 69

Which best describes the reticular formation of the brain?

A)It is mainly involved in motor coordination and balance.
B)It is the master endocrine gland of the brain.
C)It is primarily responsible for visual perception.
D)It integrates information from all regions of the CNS,and incorporates the mechanisms that regulate sleep and wakefulness.
E)It is the primary synaptic relay station for sensory information entering the CNS.

Question 70

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

Question 71

Which is one of the major inhibitory neurotransmitters in the CNS?

A)Glutamate
B)Dopamine
C)Norepinephrine
D)Gamma-aminobutyric acid (GABA)
E)Beta-endorphin

Question 72

Multiple sclerosis is a disease that primarily effects the somatic motor nervous system.  Which of the following might be symptoms of multiple sclerosis?

A)Difficulty controlling muscle movements,such as using a fork and knife to cut food
B)Inappropriate sensory sensation,such as hearing voices when in a silent room
C)Difficulty expressing appropriate emotional responses
D)Cognitive and memory decline
E)Difficulty digesting foods due to inactivity of the muscles in the walls of abdominal organs

Question 73

Which of the following does NOT result from the binding of nicotine with nicotinic acetylcholine receptors?

A)A mild form of skeletal muscle paralysis that creates a more relaxed state
B)Signal transmission at neuromuscular junctions
C)Generation of excitatory signals within autonomic ganglia
D)The release of norepinephrine,dopamine,and epinephrine
E)Facilitation of the release of multiple neurotransmitters within the brain,including the "reward pathway" involving dopamine

Question 74

You are studying a disease in which inhibition of sensory neurons is diminished,leading to more dramatic sensory sensations than are appropriate for stimulus strength.For example,when a person with this disease listens to a person talking in a normal voice,it sounds like they are yelling.  Which neurotransmitter might be expressed at lower levels in this disease compared to a healthy individual?

A)Glutamate
B)Dopamine
C)Norepinephrine
D)Gamma-aminobutyric acid (GABA)
E)Beta-endorphin

Question 75

Synthesis of neuropeptides differs from that of other neurotransmitters because it

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 76

In clinical trials,scientists discover that use of drug X results in a decrease in norepinephrine signaling.In the process of making a list of possible mechanisms of this drug to test,which of the following is NOT a plausible explanation for the effects of drug X?

A)X inhibits synthesis of norepinephrine at the axon terminal.
B)X inhibits norepinephrine release from the terminal.
C)X blocks reuptake of norepinephrine by the terminal.
D)X is an adrenergic receptor antagonist.
E)X stimulates the catabolism of norepinephrine.

Question 77

Which is a FALSE statement about the cerebrospinal fluid?

A)It has the same composition as blood plasma.
B)It acts as a cushion for the brain and spinal cord.
C)It is secreted by cells lining the ventricles of the brain.
D)It circulates within and between brain ventricles and surrounds the spinal cord.
E)It is in diffusion equilibrium with the extracellular fluid of the central nervous system. 

Question 78

The fire alarm in your building is sounding off and you are hurriedly collecting your belongings before evacuating.  Which portion of the nervous system is dominant?

A)Afferent nervous system
B)Sympathetic nervous system
C)Parasympathetic nervous system
D)Somatic motor nervous system
E)Autonomic nervous system

Question 79

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

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

Question 80

When you have a negative experience,your brain ties the emotion to the memory so that you avoid similar experiences in the future.  If you were in a bike accident,and were afraid to get on a bike again,which brain structure functional group is active in guiding your fear?

A)Diencephalon
B)Cerebrum
C)Limbic system
D)Reticular formation
E)Cerebellum