A&P Mastering Chapter 11 & Video Assignments

BioFlix Activity: How Synapses Work -- Events at a Synapse Drag the labels to identify the sequence of events that occurs at a synapse.

1. An action Potential arrives at the synaptic terminal2 Calcium channels open, and calcium ions enter the synaptic terminal3. vesicles containg neurotransmitters fuse with the plasma membrane of the sending neuron4. Neurotransmitter molecules fiffuse across synaptic cleft5. The neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, causing ion channels there to open

Which of the following is true of axons? Axons use chemically gated ion channels to generate graded potentials. A neuron can have only one axon, but the axon may have occasional branches along its length. Smaller (thinner) axons are more likely to bear myelin sheaths than larger (thicker) axons. Neurons can have multiple axons but only one dendrite.

A neuron can have only one axon, but the axon may have occasional branches along its length.

T/F: The sodium-potassium pump ejects two Na+ from the cell and then transports three K+ back into the cell in order to maintain the concentration gradients for sodium and potassium.

F

T/F: Unmyelinated fibers conduct impulses faster than myelinated fibers.

F

How do action potential propagation speeds compare in myelinated and unmyelinated axons? View Available Hint(s)for Part F How do action potential propagation speeds compare in myelinated and unmyelinated axons?Propagation in unmyelinated axons is faster over short distances, but propagation is faster in myelinated axons over long distances.Propagation is faster in myelinated axons.Propagation speeds are similar in both axon types.Propagation is faster in unmyelinated axons.

Propagation is faster in myelinated axons.

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference? View Available Hint(s)for Part A Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?Resting membrane potential (RMP)Threshold potentialAction potentialPositive membrane potential

Resting membrane potential (RMP)Threshold potentialAction potentialPositive membrane potential

Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS? satellite cells Schwann cells astrocytes oligodendrocytes

Schwann cells

Which neuroglia are the most abundant and versatile of the glial cells? astrocytes ependymal cells Schwann cells oligodendrocytes

astrocytes

A molecule that carries information across a synaptic cleft is a View Available Hint(s)for Part B A molecule that carries information across a synaptic cleft is asynaptic cleft. synapse. sending neuron. neurotransmitter. receiving neuron.

neurotransmitter.

Which of the following are gaps found along a myelin sheath? outer collar of perinuclear cytoplasm nodes of Ranvier terminal boutons axolemma

nodes of Ranvier

Which of the following types of glial cells produces the myelin sheaths that insulate axons, or nerve fibers, in the central nervous system (CNS)? microglia oligodendrocytes ependymal cells astrocytes

oligodendrocytes

Which of the following is NOT a type of circuit? converging circuits diverging circuits reverberating circuits pre-discharge circuits

pre-discharge circuits

Which of the following is NOT one of the basic functions of the nervous system? integration of sensory input monitor changes occurring both inside and outside the body control the activity of muscles and glands regulation of neurogenesis

regulation of neurogenesis

Art Question Chapter 11 Question 23 Which of the following most accurately describes the involvement of the structure labeled B in synaptic signaling? release of neurotransmitter into the synaptic cleft by active transport release of Ca2+ into the synaptic cleft by exocytosis release of neurotransmitter into the synaptic cleft by exocytosis release of Na+ and/or K+ ions into the synaptic cleft by facilitated diffusion

release of neurotransmitter into the synaptic cleft by exocytosis

The __________ is due to the difference in K+ and Na+ concentrations on either side of the plasma membrane, and the difference in permeability of the membrane to these ions. dendrite potential active potential resting membrane potential intermittent membrane potential

resting membrane potential

In addition to diffusion, what are two other mechanisms that terminate neurotransmitter activity? View Available Hint(s)for Part G In addition to diffusion, what are two other mechanisms that terminate neurotransmitter activity? excitation and degradation reuptake and inhibition exocytosis and degradation reuptake and degradation

reuptake and degradation

Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking)? reverberating circuits converging circuits diverging circuits parallel after-discharge circuits

reverberating circuits

The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________. View Available Hint(s)for Part G The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________.continuous conductionsaltatory conductionmyelinated conductionlocal conduction

saltatory conduction

The small space between the sending neuron and the receiving neuron is the View Available Hint(s)for Part A The small space between the sending neuron and the receiving neuron is theneurotransmitter. synaptic cleft. calcium channel. synaptic terminal. vesicle.

synaptic cleft.

Which criterion is used to functionally classify neurons? the direction in which the nerve impulse travels relative to the central nervous system whether the neurons are found within the CNS or the PNS the number of processes extending from the cell body neuron whether the nerve fibers are myelinated or unmyelinated

the direction in which the nerve impulse travels relative to the central nervous system

Imagine you changed the concentration of K+ outside a neuron such that the resting membrane potential changed to -80 mV (from the normal resting value of -70 mV). What have you changed? View Available Hint(s)for Part F Imagine you changed the concentration of K+ outside a neuron such that the resting membrane potential changed to -80 mV (from the normal resting value of -70 mV). What have you changed?the concentration gradient for K+the electrical gradients and concentration gradients for both Na+ and K+.the electrical gradient for K+the electrical gradient for K+ and the concentration gradient for K+

the electrical gradient for K+ and the concentration gradient for K+

Events that occur during synaptic activity are listed here, but they are arranged in an incorrect order. Choose the correct order of these events below. (a) Voltage-gated calcium channels open (b) Neurotransmitter binds to receptors (c) Action potential arrives at axon terminal (d) Neurotransmitter is removed from the synaptic cleft (e) Neurotransmitter released into synaptic cleft (f) Graded potential generated in postsynaptic cell View Available Hint(s)for Part H Events that occur during synaptic activity are listed here, but they are arranged in an incorrect order. Choose the correct order of these events below. (a) Voltage-gated calcium channels open (b) Neurotransmitter binds to receptors (c) Action potential arrives at axon terminal (d) Neurotransmitter is removed from the synaptic cleft (e) Neurotransmitter released into synaptic cleft (f) Graded potential generated in postsynaptic cell (a) Voltage-gated calcium channels open (e) Neurotransmitter released into the synaptic cleft (c) Action potential arrives at axon terminal (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell (d) Neurotransmitter is removed from the synaptic cleft (d) Neurotransmitter is removed from the synaptic cleft (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell (c) Action potential arrives at axon terminal (a) Voltage-gated calcium channels open (e) Neurotransmitter released into the synaptic cleft (c) Action potential arrives at axon terminal (a) Voltage-gated calcium channels open (e) Neurotransmitter released into synaptic cleft (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell (d) Neurotransmitter is removed from the synaptic cleft (c) Action potential arrives at axon terminal (a) Voltage-gated calcium channels open (e) Neurotransmitter released into the synaptic cleft (d) Neurotransmitter is removed from the synaptic cleft (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell

(c) Action potential arrives at axon terminal (a) Voltage-gated calcium channels open (e) Neurotransmitter released into synaptic cleft (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell (d) Neurotransmitter is removed from the synaptic cleft

Art Question Chapter 11 Question 18 At which point of the illustrated action potential are the most gated Na+ channels open? A B C D E

B

Art Question Chapter 11 Question 7 Which lettered region in the figure is referred to as the soma? A B C D E

B

Art Question Chapter 11 Question 11 In which area of the neuron is an action potential initially generated? A B C D E

C

What is the role of calcium in synaptic activity? View Available Hint(s)for Part C What is the role of calcium in synaptic activity? Calcium degrades neurotransmitter in the synaptic cleft. Calcium influx into the synaptic terminal causes vesicle fusion. Calcium influx into the axon causes an action potential to propagate into the synaptic terminal. Calcium diffuses across the synaptic cleft and binds to receptors on the postsynaptic neuron.

Calcium influx into the synaptic terminal causes vesicle fusion.

What type of conduction takes place in unmyelinated axons? View Available Hint(s)for Part A What type of conduction takes place in unmyelinated axons?Continuous conductionSynaptic transmissionElectrical conductionSaltatory conduction

Continuous conduction

Art Question Chapter 11 Question 10 Which area would contain an abundance of vesicles containing neurotransmitters? A B C D E

E

What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization? View Available Hint(s)for Part E What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization?Activation gates of voltage-gated Na+‎ channels close, while inactivation gates of voltage-gated K+‎ channels open.Inactivation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open. Inactivation gates of voltage-gated Na+‎ channels close, while inactivation gates of voltage-gated K+‎ channels open.Activation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open.

Inactivation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open.

Where do most action potentials originate? View Available Hint(s)for Part A Where do most action potentials originate?Nodes of RanvierAxon terminalInitial segmentCell body

Initial segment

During the hyperpolarization phase of the action potential, when the membrane potential is more negative than the resting membrane potential, what happens to voltage-gated ion channels? View Available Hint(s)for Part F During the hyperpolarization phase of the action potential, when the membrane potential is more negative than the resting membrane potential, what happens to voltage-gated ion channels?K+ channels open. Na+ channels inactivate.K+ channels close. Leakage channels open.K+ channels close. Na+ channels open.K+ channels close. Na+ channels go from an inactivated state to a closed state.

K+ channels close. Na+ channels go from an inactivated state to a closed state.

Which of the following is the clearest example of a neuronal membrane's selective permeability? View Available Hint(s)for Part C Which of the following is the clearest example of a neuronal membrane's selective permeability?Diffusion of K+ ions out of the neuron causes the membrane potential to become more negative.The concentration gradient for Na+ ions is inward, but the concentration gradient for K+ ions is outward.K+ ions can diffuse across the membrane more easily than Na+ ions.The Na+-K+ pump only transports Na+ and K+ ions.

K+ ions can diffuse across the membrane more easily than Na+ ions.

During an action potential, hyperpolarization beyond (more negative to) the resting membrane potential is primarily due to __________. View Available Hint(s)for Part E During an action potential, hyperpolarization beyond (more negative to) the resting membrane potential is primarily due to __________.Na+ diffusing through voltage-gated channelsK+ ions diffusing through leakage channelsNa+-K+ pump activityK+ ions diffusing through voltage-gated channels

K+ ions diffusing through voltage-gated channels

The repolarization phase of the action potential, where voltage becomes more negative after the +30mV peak, is caused primarily by __________. View Available Hint(s)for Part D The repolarization phase of the action potential, where voltage becomes more negative after the +30mV peak, is caused primarily by __________.Na+ ions transported out of the cell by the Na+-K+ pumpK+ ions leaving the cell through voltage-gated channelsNa+ ions leaving the cell through voltage-gated channelsK+ ions entering the cell through voltage-gated channels

K+ ions leaving the cell through voltage-gated channels

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel? View Available Hint(s)for Part B Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?Sodium-potassium ATPasesLigand-gated channelsVoltage-gated channelsLeak channels

Leak channels

What is happening to voltage-gated channels at this point in the action potential? View Available Hint(s)for Part B What is happening to voltage-gated channels at this point in the action potential?Na+ channels are inactivating, and K+ channels are closing.Na+ channels are inactivating, and K+ channels are opening.Na+ channels are opening, and K+ channels are closing.Both Na+ and K+ channels are opening.

Na+ channels are inactivating, and K+ channels are opening.

In which type of axon will velocity of action potential conduction be the fastest? View Available Hint(s)for Part F In which type of axon will velocity of action potential conduction be the fastest?Myelinated axons with the smallest diametersUnmyelinated axons of the shortest lengthMyelinated axons with the largest diameterUnmyelinated axons with the largest diameter

Myelinated axons with the largest diameter

The diffusion of what ion, across the neuronal membrane, is responsible for the local currents that depolarize regions of the axon to threshold? View Available Hint(s)for Part A The diffusion of what ion, across the neuronal membrane, is responsible for the local currents that depolarize regions of the axon to threshold?voltage-gated Na+ (sodium) channelsCa2+ (calcium)Na+ (sodium)K+ (potassium)

Na+ (sodium)

During the action potential of a neuron, which ion is primarily crossing the membrane during the depolarization phase, and in which direction is the ion moving? View Available Hint(s)for Part A During the action potential of a neuron, which ion is primarily crossing the membrane during the depolarization phase, and in which direction is the ion moving?K+ is entering the cell.Na+ is exiting the cell.Na+ is entering the cell.K+ is exiting the cell.

Na+ is entering the cell.

What prevents the Na+ and K+ gradients from dissipating? View Available Hint(s)for Part F What prevents the Na+ and K+ gradients from dissipating?H+-K+ ATPaseNa+ cotransporterNa+ and K+ leaksNa+-K+ ATPase

Na+-K+ ATPase

What is the direct role of neurotransmitter at a chemical synapse? View Available Hint(s)for Part D What is the direct role of neurotransmitter at a chemical synapse? Neurotransmitter causes a graded potential in the postsynaptic cell. Neurotransmitter causes vesicles to fuse with the presynaptic membrane. Neurotransmitter causes calcium to flood into the presynaptic cell. Neurotransmitter binds to receptors on the postsynaptic cell membrane and allows ions to diffuse across the membrane.

Neurotransmitter binds to receptors on the postsynaptic cell membrane and allows ions to diffuse across the membrane.

What characterizes repolarization, the second phase of the action potential? View Available Hint(s)for Part D What characterizes repolarization, the second phase of the action potential?Once the membrane depolarizes to a threshold value of approximately -55 mV, it repolarizes to its resting value of -70 mV.As the membrane repolarizes to a negative value, it goes beyond the resting state to a value of -80 mV.Before the membrane has a chance to reach a positive voltage, it repolarizes to its negative resting value of approximately -70 mV.Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

T/F: Neurons are also called nerve cells.

T

T/F: Opening K+ or Cl- channels in a postsynaptic membrane would produce an inhibitory postsynaptic potential (IPSP).

T

Which of the following best describes the Na+ and K+ concentrations across a neuron's plasma membrane? View Available Hint(s)for Part A Which of the following best describes the Na+ and K+ concentrations across a neuron's plasma membrane?The Na+ concentration is higher outside the cell compared to inside. The K+ concentration is higher inside the cell compared to outside.Both Na+ and K+ concentrations are higher inside the cell compared to outside.The Na+ concentration is higher inside the cell compared to outside. The K+ concentration is higher outside the cell compared to inside.Both Na+ and K+ concentrations are higher outside the cell compared to inside.

The Na+ concentration is higher outside the cell compared to inside. The K+ concentration is higher inside the cell compared to outside.

Tetraethylammonium (TEA) blocks voltage-gated K+ channels such that K+ cannot pass even when the channels are open. However, TEA leaves K+ leakage channels largely unaffected. How would you expect the action potential to change if you treated a neuron with TEA? View Available Hint(s)for Part G Tetraethylammonium (TEA) blocks voltage-gated K+ channels such that K+ cannot pass even when the channels are open. However, TEA leaves K+ leakage channels largely unaffected. How would you expect the action potential to change if you treated a neuron with TEA?The membrane would depolarize as usual but then stay at that depolarized voltage (about +30 mV).The action potential would depolarize as usual, but the repolarization phase would take longer, causing the action potential to be more broad in time.The action potential would fail. Once the voltage reached threshold, it would return to the resting membrane potential.The membrane would depolarize and repolarize as usual, but no hyperpolarization beyond (more negative to) the resting membrane potential would occur.

The action potential would depolarize as usual, but the repolarization phase would take longer, causing the action potential to be more broad in time.

Why does regeneration of the action potential occur in one direction, rather than in two directions? View Available Hint(s)for Part C Why does regeneration of the action potential occur in one direction, rather than in two directions?The activation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just depolarized.The inactivation gates of voltage-gated K+‎ channels close in the node, or segment, that has just fired an action potential.The inactivation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just fired an action potential.The activation gates of voltage-gated K+‎ channels open in the node, or segment, that has just depolarized.

The inactivation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just fired an action potential.

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you? View Available Hint(s)for Part C On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?The outside surface of the plasma membrane is much more negatively charged than the inside surface.The inside surface of the plasma membrane is much more positively charged than the outside surface.The inside surface of the plasma membrane is much more negatively charged than the outside surface.There is no electrical potential difference between the inside and the outside surfaces of the plasma membrane.

The inside surface of the plasma membrane is much more negatively charged than the outside surface.

What characterizes depolarization, the first phase of the action potential? View Available Hint(s)for Part C What characterizes depolarization, the first phase of the action potential?The membrane potential changes from a negative value to a positive value.The membrane potential changes to a less negative (but not a positive) value.The membrane potential reaches a threshold value and returns to the resting state.The membrane potential changes to a much more negative value.

The membrane potential changes from a negative value to a positive value.

What event triggers the generation of an action potential? View Available Hint(s)for Part E What event triggers the generation of an action potential?The membrane potential must hyperpolarize from the resting voltage of -70 mV to the more negative value of -80 mV.The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.The membrane potential must depolarize from the resting voltage of -70 mV to its peak value of +30 mV.The membrane potential must return to its resting value of -70 mV from the hyperpolarized value of -80 mV.

The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.

What is the function of the myelin sheath? View Available Hint(s)for Part D What is the function of the myelin sheath?The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals. The myelin sheath increases the insulation along the entire length of the axon.The myelin sheath decreases the resistance of the axonal membrane to the flow of charge.The myelin sheath decreases the speed of action potential conduction from the initial segment to the axon terminals.

The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals.

In a myelinated axon, how do the nodes of Ranvier differ from other segments of the same axon? View Available Hint(s)for Part D In a myelinated axon, how do the nodes of Ranvier differ from other segments of the same axon?The nodes are more permeable to ions.The nodes are longer segments of the axon.The nodes are less numerous.The nodes are wrapped in myelin.

The nodes are more permeable to ions.

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors. View Available Hint(s)for Part E The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors.The presence of concentration gradients and voltage-gated channelsThe presence of a resting membrane potential and leak channelsThe presence of concentration gradients and Na+-K+ pumpsThe presence of concentration gradients and leak channels

The presence of concentration gradients and leak channels

During action potential propagation in an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction? View Available Hint(s)for Part C During action potential propagation in an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction?Positive charges only move in one direction after they enter the cell.The extracellular sodium concentration is too low around the previous axonal segment for an action potential to be (re)generated.New action potential generation near the soma repels previously generated action potentials, causing them to always propagate away from the soma.The previous axonal segment is in the refractory period.

The previous axonal segment is in the refractory period.

Hypothetically, what would be the most immediate effect of doubling the number of Na+ leakage channels in the plasma membrane? View Available Hint(s)for Part H Hypothetically, what would be the most immediate effect of doubling the number of Na+ leakage channels in the plasma membrane?The inward concentration gradient for Na+ would become larger.The outward concentration gradient for K+ would become smaller.The resting membrane potential would become more negative.The resting membrane potential would become less negative (more positive).

The resting membrane potential would become less negative (more positive).

Suppose a drug is developed that blocks K+ leakage channels. The drug prevents ions from passing through those channels. If this drug was applied to a neuron, what would be the most immediate effect on that neuron? View Available Hint(s)for Part E Suppose a drug is developed that blocks K+ leakage channels. The drug prevents ions from passing through those channels. If this drug was applied to a neuron, what would be the most immediate effect on that neuron?The resting membrane potential would become more negative.The concentration gradient for K+ would decrease.The resting membrane potential would become less negative (more positive).The concentration gradient for Na+ would decrease.

The resting membrane potential would become less negative (more positive).

The myelin on myelinated neurons can be degraded or destroyed in diseases such as multiple sclerosis-a process called demyelination. If a myelinated neuron was affected by demyelination, how would this affect action potentials in that neuron? View Available Hint(s)for Part H The myelin on myelinated neurons can be degraded or destroyed in diseases such as multiple sclerosis-a process called demyelination. If a myelinated neuron was affected by demyelination, how would this affect action potentials in that neuron?Action potentials would propagate in both directions along the axon.The speed of action potential propagation would be faster.Initial generation of action potentials would be more difficult.The speed of action potential propagation would be slower.

The speed of action potential propagation would be slower.

The plasma membrane is much more permeable to K+ than to Na+. Why? View Available Hint(s)for Part D The plasma membrane is much more permeable to K+ than to Na+. Why?There are many more K+ leak channels than Na+ leak channels in the plasma membrane.The Na+-K+ pumps transport more K+ into cells than Na+ out of cells.There are many more voltage-gated K+ channels than voltage-gated Na+ channels.Ligand-gated cation channels favor a greater influx of Na+ than K+.

There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

What opens first in response to a threshold stimulus? View Available Hint(s)for Part B What opens first in response to a threshold stimulus?Voltage-gated Na+ channelsLigand-gated cation channelsLigand-gated Cl- channelsVoltage-gated K+ channels

Voltage-gated Na+ channels

What is the first change to occur in response to a threshold stimulus? View Available Hint(s)for Part F What is the first change to occur in response to a threshold stimulus?Voltage-gated Ca2+ channels change shape, and their activation gates open.Voltage-gated K+ channels change shape, and their activation gates open.Voltage-gated Na+ channels change shape, and their activation gates open.Voltage-gated Na+ channels change shape, and their inactivation gates close.

Voltage-gated Na+ channels change shape, and their activation gates open.

What type of channel on the postsynaptic membrane binds neurotransmitter? View Available Hint(s)for Part F What type of channel on the postsynaptic membrane binds neurotransmitter? a voltage-gated channel a mechanically gated channel a leakage channel a chemically gated channel

a chemically gated channel

A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell? View Available Hint(s)for Part A A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell? a secretory cell a neuron a muscle cell a Schwann cell

a neuron

What type of stimulus is required for an action potential to be generated? multiple stimuli a suprathreshold stimulus a threshold level depolarization hyperpolarization

a threshold level depolarization

During what part of the action potential do voltage-gated Na+ channels begin to inactivate (their inactivation gates close)? View Available Hint(s)for Part C During what part of the action potential do voltage-gated Na+ channels begin to inactivate (their inactivation gates close)?at the beginning of an action potential, as the membrane potential reaches thresholdat the end of the repolarization phase, as the membrane potential briefly passes its resting valueat the end of the depolarization phase, as the membrane potential approaches its peak valueat the end of the hyperpolarization phase of an action potential, as the membrane potential returns to its resting value

at the end of the depolarization phase, as the membrane potential approaches its peak value

Where are action potentials regenerated as they propagate along a myelinated axon? View Available Hint(s)for Part E Where are action potentials regenerated as they propagate along a myelinated axon?at the myelinated segmentsat every segment of the axonat the axon hillockat the nodes of Ranvier

at the nodes of Ranvier

Which part of the neuron is responsible for generating a nerve impulse? soma axon dendrite chromatophilic substance

axon

What part of the nervous system performs information processing and integration? somatic nervous system sympathetic nervous system central nervous system parasympathetic nervous system

central nervous system

Which component has a role in the postsynaptic cell during synaptic activity? View Available Hint(s)for Part B Which component has a role in the postsynaptic cell during synaptic activity? calcium channels Vesicles filled with neurotransmitter chemically gated channels axon terminal

chemically gated channels

Which of the following is a factor that determines the rate of impulse propagation, or conduction velocity, along an axon? degree of myelination of the axon the number of axon collaterals extending from a truncated axon length of the axon whether the axon is located in the central nervous system or in the peripheral nervous system

degree of myelination of the axon

An action potential is self-regenerating because __________. View Available Hint(s)for Part B An action potential is self-regenerating because __________.repolarizing currents established by the efflux of Na+‎ flow down the axon and trigger an action potential at the next segmentrepolarizing currents established by the efflux of K+‎ flow down the axon and trigger an action potential at the next segmentdepolarizing currents established by the influx of K+‎ flow down the axon and trigger an action potential at the next segmentdepolarizing currents established by the influx of Na+‎ flow down the axon and trigger an action potential at the next segment

depolarizing currents established by the influx of Na+‎ flow down the axon and trigger an action potential at the next segment

Which membrane potential occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron? inhibitory action potential action potential inhibitory postsynaptic potential excitatory postsynaptic potential

excitatory postsynaptic potential

Neurotransmitter is released from presynaptic neurons through what mechanism? View Available Hint(s)for Part E Neurotransmitter is released from presynaptic neurons through what mechanism? pinocytosis phagocytosis exocytosis endocytosis

exocytosis

What component of the reflex arc determines the response to a stimulus? sensory neuron integration center receptor effector

integration center

When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, View Available Hint(s)for Part D When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron,the receiving neuron becomes more negative inside. ion channels in the plasma membrane of the receiving neuron open. ion channels in the plasma membrane of the sending neuron open. vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron. the receiving neuron becomes more positive inside.

ion channels in the plasma membrane of the receiving neuron open.

What is the major role of the Na+-K+ pump in maintaining the resting membrane potential? View Available Hint(s)for Part B What is the major role of the Na+-K+ pump in maintaining the resting membrane potential?maintaining the concentration gradients for Na+ and K+ across the cell membranehydrolyzing ATPpermitting Na+ and K+ ions to diffuse across the plasma membranemaking the membrane potential negative by moving more Na+ ions out of the cell than K+ ions into the cell

maintaining the concentration gradients for Na+ and K+ across the cell membrane

Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons? oligodendrocytes ependymal cells astrocytes microglia

microglia

Which of the following would increase the membrane permeability to K+? View Available Hint(s)for Part D Which of the following would increase the membrane permeability to K+?more K+ leakage channelsa greater concentration gradient for K+more Na+ leakage channelsmore negative membrane potential

more K+ leakage channels

Which of the following types of neurons carry impulses away from the central nervous system (CNS)? association motor afferent sensory

motor

Art Question Chapter 11 Question 22 What event is depicted in the structure labeled A? movement of Na+ into the interior of the axonal terminus through chemically gated channels movement of neurotransmitters into the interior of the axonal terminus through chemically gated channels movement of Ca2+ into the interior of the axonal terminus through voltage-gated channels movement of the action potential into the interior of the axonal terminus through voltage-gated channels

movement of Ca2+ into the interior of the axonal terminus through voltage-gated channels

Art Question Chapter 11 Question 8 What structural classification describes this neuron? multipolar unipolar nonpolar bipolar

multipolar

An action potential in one segment of axon causes adjacent sections of axon membrane to reach threshold through what mechanism? View Available Hint(s)for Part B An action potential in one segment of axon causes adjacent sections of axon membrane to reach threshold through what mechanism?Na+ ions diffusing across the membrane through leakage channelsthe generation of local currentsneurotransmitters causing chemically gated channels to openK+ ions diffusing through voltage-gated channels

the generation of local currents

If a signal from a sending neuron makes the receiving neuron more negative inside, View Available Hint(s)for Part E If a signal from a sending neuron makes the receiving neuron more negative inside,the sending neuron becomes more negative inside. the sending neuron becomes more positive inside. the receiving neuron immediately generates an action potential. the receiving neuron is more likely to generate an action potential. the receiving neuron is less likely to generate an action potential.

the receiving neuron is less likely to generate an action potential.

Which of the following allows us to consciously control our skeletal muscles? the parasympathetic division of the autonomic nervous system the afferent division of the nervous system the sympathetic division of the autonomic nervous system the somatic nervous system

the somatic nervous system

What is the electrochemical gradient of an ion? View Available Hint(s)for Part G What is the electrochemical gradient of an ion?the difference between the inside and outside concentrations of that ionthe membrane potential at which the electrical gradient and concentration gradient for that ion are equal in magnitude, but opposite in directionthe sum of the electrical and concentration gradients for that ionthe direction an ion would tend to diffuse based on the membrane potential

the sum of the electrical and concentration gradients for that ion

When calcium ions enter the synaptic terminal, View Available Hint(s)for Part C When calcium ions enter the synaptic terminal,the inside of the receiving neuron becomes more positive. they cause an action potential in the sending neuron. they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron. the inside of the receiving neuron becomes more negative. neurotransmitter molecules are quickly removed from the synaptic cleft.

they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.