Physiology Ch 7 Assignment and Quiz

Where is dopamine needed to relieve the symptoms of Parkinson's disease? Substantia nigra Skeletal muscles Basal nuclei Red nucleus

Basal nuclei

An action potential arriving at the presynaptic terminal causes __________. voltage-gated sodium ion channels to open, and sodium ions to diffuse into the cell voltage-gated sodium ion channels to open, and sodium ions to diffuse out of the cell voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell acetylcholine to diffuse into the cell ligand-gated sodium channels to open, and sodium ions to diffuse out of the cell

voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell

Ion channels that open in response to depolarization are called ________. voltage-gated channels potential-gated channels ion-gated channels stimulation-gated channels

voltage-gated channels

What is NOT true of the relative refractory period? -Na+ channels are inactivated -Many Na+ channels are returning to a closed state -K+ is moving out of the axon through its open channels -A strong stimulus could cause a depolarization

-Na+ channels are inactivated

Saxitoxin is a neurotoxin sometimes produced by shellfish. Saxitoxin prevents Na+ gated channels from opening. Which of the following would produce the same signs as saxitoxin poisoning? -A chemical that inhibited the formation of ACh in the synaptic knob -ACh esterase inhibition -A chemical that binds to a voltagegted K+ channels that prevents them from opening -A chemical that binds to ligandgated receptors that prevents them from closingc

A chemical that inhibited the formation of ACh in the synaptic knob

Sandra had ptosis (droopy eyelid) which most likely resulted from the Botox. Which of the following is a mechanism that would cause this sign of botulinum toxin exposure? -ACh esterase inhibition -A chemical that binds to ligandgated receptors that prevents them from closing -A chemical that prevents the release of ACh from the presynaptic neuron -A chemical that binds to a voltagegated K+ channels that prevents them from opening

A chemical that prevents the release of ACh from the presynaptic neuron

If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result? -Acetylcholine would build up in the synaptic cleft. -Acetylcholine present in the synaptic cleft would no longer depolarize the postsynaptic membrane. -Acetylcholine synthesis would immediately cease. -Neurotransmitter-filled synaptic vesicles would be unable to fuse and release their products into the synaptic cleft.

Acetylcholine would build up in the synaptic cleft.

If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result? Neurotransmitter-filled synaptic vesicles would be unable to fuse and release their products into the synaptic cleft. Acetylcholine synthesis would immediately cease. Acetylcholine present in the synaptic cleft would no longer depolarize the postsynaptic membrane. Acetylcholine would build up in the synaptic cleft.

Acetylcholine would build up in the synaptic cleft.

Retrograde transport ________. moves substances toward the cell body moves membranes, vesicles, and viruses uses molecular motor proteins of dynein All of the choices are correct.

All of the choices are correct.

Which of the following are natural analgesics? Endorphins Enkephalins Dynorphins All of the choices are correct.

All of the choices are correct.

Which of the following is/are a characteristic of GABA as a neurotransmitter? Multiple Choice All of the choices are correct. It is inhibitory It opens Cl- channels into the cell It helps control voluntary movement

All of the choices are correct.

What is the action of the binding of muscarine to its receptors in the digestive system? Beta-gamma subunits bind to K+ channels, open them, leading to hyperpolarization. Alpha subunits bind to K+ channels, open them, leading to hyperpolarization. Alpha subunits bind to K+ channels, close them, leading to depolarization. Beta-gamma subunits bind to K+ channels, close them, leading to depolarization.

Alpha subunits bind to K+ channels, close them, leading to depolarization.

Which of the following is NOT true of long-term potentiation (LTP)? Repeated stimulation enhance excitability Associated with the removal of AMPA glutamate receptors It is a form of synaptic plasticity Associated with insertion of AMPA glutamate receptors

Associated with the removal of AMPA glutamate receptors

If a drug was developed that interfered with the proper functioning of the microtubules found within the axons of neurons, how would you expect this to impact axonal transport processes? -Retrograde transport would cease -.Both anterograde and retrograde transport processes would cease. -The production of substances within the cell body would cease. -Anterograde transport would cease.

Both anterograde and retrograde transport processes would cease.

The enzyme choline acetyltransferase catalyzes the reaction between acetyl-CoA and choline resulting in the formation of the neurotransmitter acetylcholine. This enzyme is produced within the cell body of neurons, but the synthesis of acetylcholine occurs within the axon terminals. Which statement best describes the axonal transport mechanism associated with this process? -Acetylcholine is transported in the anterograde direction. -Acetylcholine is transported in the retrograde direction -.Choline acetyltransferase is transported in the anterograde direction. -Choline acetyltransferase is transported in the retrograde direction.

Choline acetyltransferase is transported in the anterograde direction.

Where is glycine released? In the CNS At the diaphragm In the PNS from the motor neurons innervating skeletal muscles

In the CNS

What is the effect of the neurotransmitter at the neuromuscular junction? It increases the calcium ion permeability of the presynaptic membrane. It increases the sodium ion permeability of the presynaptic membrane. It depolarizes the presynaptic membrane by increasing the permeability of sodium ions. It causes ligand gated sodium channels in the muscle fiber to increase their permeability to sodium, which depolarizes the postsynaptic membrane. It causes ligand gated calcium channels in the muscle fiber to increase their permeability to calcium, which depolarizes the postsynaptic membrane.

It causes ligand gated sodium channels in the muscle fiber to increase their permeability to sodium, which depolarizes the postsynaptic membrane.

Acetylcholine has which effect on the postsynaptic neuron? Ligand-gated calcium ion channels open and calcium diffuses inward. Ligand-gated sodium ion channels open and sodium diffuses inward. Terminal vessels migrate to the plasma membrane. Voltage-gated calcium ion channels open and calcium diffuses inward. Voltage-gated sodium ion channels open and sodium diffuses inward.

Ligand-gated sodium ion channels open and sodium diffuses inward.

What degrades and inactivates dopamine after it has stimulated the postsynaptic neuron? Monoamine oxidase Norepinephrine Acetylcholinesterase Serotonin

Monoamine oxidase

During depolarization, which of the following statements about voltage-gated ion channels is TRUE? K+ gates open before Na+ gates. Na+ gates open before K+ gates. Na+ and K+ gates open at the same time. Na+ gates open while K+ gates remain closed. K+ gates open while Na+ gates remain closed.

Na+ gates open before K+ gates.

What is the nigrostriatal tract? Neural tracts that release serotonin Neural tracts involved with mood and emotion Neural tracts that release dopamine and are involved in motor control Neural tracts that release dopamine

Neural tracts that release dopamine and are involved in motor control

_______________ the time between signals sent from the same presynaptic terminal increases the strength of the graded potential. This is an example of ________________ summation. Increasing; temporal Reducing; spatial Reducing; temporal Increasing; spatial

Reducing; temporal

Suppose that a new virus is discovered that specifically infects motor neurons. Assume that this virus enters neurons in conjunction with choline molecules. Once inside the cell, the virus enters the nucleus and replicates. Which direction describes the axonal transport route taken by this virus? Retrograde transport Anterograde transport

Retrograde transport

Synaptic vesicles are docked to the plasma membrane of the axon terminal by a protein complex called ________. connexins synaptotagmins boutons SNARE

SNARE

Which of the following occurs when an action potential arrives at the presynaptic terminal? Synaptic vessels fuse with the plasma membrane and release acetylcholine. Acetylcholine is actively transported from the presynaptic neuron. Acetylcholine is actively transported to the postsynaptic neuron. Ligand-gated sodium channels open. Sodium ions diffuse into the cell.

Synaptic vessels fuse with the plasma membrane and release acetylcholine.

Which of the following statements about the resting membrane potential is TRUE? The exterior of the cell has a net negative charge and the interior has a net positive charge. The exterior of the cell has a net negative charge and the interior is neutral. The exterior of the cell has a net positive charge and the interior has a net negative charge. The exterior of the cell has a net positive charge and the interior is neutral.

The exterior of the cell has a net positive charge and the interior has a net negative charge.

If demyelination occurs, why don't action potentials occur at regions of the axon that were previously myelinated? -A much thicker plasma membrane is present within these regions of the axon. -These regions lack the appropriate concentration of voltage-gated sodium channels. -A much thinner plasma membrane is present within these regions of the axon. -These regions contain too high of a concentration of voltage-gated sodium channels to work appropriately.

These regions lack the appropriate concentration of voltage-gated sodium channels.

What do muscarine and nicotine have in common? They are both agonists for their respective receptors. They both activate-protein coupled channels. They are both always excitatory. They are both antagonists for their respective receptors.

They are both agonists for their respective receptors.

Indicate the summative effect that brings the initial segment closest to threshold. Two EPSPs in proximity to each other Two IPSPs located a large distance apart One IPSP and one EPSP in proximity to each other Two EPSPs located a large distance apart Two IPSPs in proximity to each other

Two EPSPs in proximity to each other

What amino acid is a precursor of dopamine? Tryptophan Tyrosine Serine Leucine

Tyrosine

Action potentials would be conducted most rapidly by ________. a 40 mm diameter unmyelinated axon a 10 mm diameter unmyelinated axon a 40 mm diameter myelinated axon a 10 mm diameter myelinated axon

a 10 mm diameter myelinated axon

The neurotransmitter at the neuromuscular junction is ___________. adrenaline dopamine acetylcholine histamine serotonin

acetylcholine

The most numerous of all cells of CNS nervous tissue are the ________. -astrocytes -microglia -neurons -Schwann cells

astrocytes

Neurotransmitters ________. are actively transported across the synaptic cleft are released by endocytosis bind to voltage-gated channels bind to chemically-gated or ligand-gated channels

bind to chemically-gated or ligand-gated channels

Acetylcholine diffuses across the synaptic cleft and ________. binds to voltage-gated sodium channels directly initiates a new action potential on the postsynaptic membrane causes potassium leak channels to close binds to ACh receptors that open ligand-gated sodium channels

binds to ACh receptors that open ligand-gated sodium channels

Neurotransmitter release would be inhibited by ________. stimulating protein kinase activity blocking Ca2+ influx in the axon terminal blocking repolarization of the axon terminal stimulating repolarization of the axon terminal

blocking Ca2+ influx in the axon terminal

At the synaptic knob, voltage-gated ______________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis. sodium potassium calciumc hloride

calcium

At the synaptic terminal, voltage-gated ______________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis. sodium calcium potassium chloride

calcium

An action potential arriving at the presynaptic terminal causes __________. sodium ions to diffuse into the cell acetylcholine to diffuse into the cell calcium ions to diffuse into the cell sodium ions to diffuse out of the cell ligand-gated sodium channels to open

calcium ions to diffuse into the cell

The arrival of the action potential at the presynaptic terminal causes ________. acetylcholine to be directly released potassium leak channels to close voltage-gated sodium channels to open calcium to enter the presynaptic terminal through voltage-gated calcium channels

calcium to enter the presynaptic terminal through voltage-gated calcium channels

Axonal transport ________. -can occur in both an anterograde and retrograde direction -is a passive process -has two fast and one slow components -can only transport signals in a retrograde direction

can occur in both an anterograde and retrograde direction

Substances that cause facilitation of a neuron ____________________________. alter the resting membrane potential of a presynaptic neuron by making it hyperpolarizedc ause the neuron to fire that may not under the same circumstances in the absence of the facilitator disable the trigger zone of the axon hillock, thereby preventing it from reaching threshold continually create additional ligand-gated ion channels at the receptor region

cause the neuron to fire that may not under the same circumstances in the absence of the facilitator

An action potential __________. -causes the neuron cell membrane to become unable to alter its charge -causes the outside of the neuron cell membrane to become positively charged in reference to the inside -causes the inside of the neuron cell membrane to become positively charged in reference to the outside -causes the inside of the neuron cell membrane to become negatively charged in reference to the outside -causes the inside of the neuron cell membrane to become neutrally charged in reference to the outside

causes the inside of the neuron cell membrane to become positively charged in reference to the outside

A resting membrane potential of -70 mV indicates that the ________________. -negative ions are only present within the cytosol and are lacking in the extracellular fluid -charges lining the inside of the plasma membrane are negative compared to the charges lining the outside -positive ions outnumber the negative ions within the cytosol -negative ions will always move into a cell

charges lining the inside of the plasma membrane are negative compared to the charges lining the outside

A resting membrane potential of -70 mV indicates that the ________________. -positive ions outnumber the negative ions within the cytosol -negative ions will always move into a cell -charges lining the inside of the plasma membrane are negative compared to the charges lining the outside -negative ions are only present within the cytosol and are lacking in the extracellular fluid

charges lining the inside of the plasma membrane are negative compared to the charges lining the outside

Demyelinating diseases cause a(n) ______________ in the conduction velocity of action potentials. increase decrease

decrease

An action potential generates local currents that tend to __________ the membrane immediately adjacent to the action potential. depolarize repolarize hyperpolarize stabilize neutralize

depolarize

At the neuromuscular junction, acetylcholine __________. diffuses across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber is actively transported across the synaptic cleft and causes calcium ions to diffuse into the postsynaptic muscle fiber diffuses across the synaptic cleft and causes calcium ions to diffuse into the postsynaptic muscle fiber diffuses across the synaptic cleft and causes sodium ions to diffuse out of the postsynaptic muscle fiber is actively transported across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber

diffuses across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber

Inhibition of neuropeptide Y synthesis would ________. induce euphoria stimulate leptin secretion induce obesity diminish appetite

diminish appetite

Action potentials occur ____________________________. in myelinated regions of an axon in both unmyelinated and myelinated regions of an axon and the dendrites in the unmyelinated regions of an axon

in the unmyelinated regions of an axon

Catecholamines activate postsynaptic cells by ________. increased Ca2+ influx into the target cell inhibition of adenylate cyclase increased production of cyclic AMP inhibition of calmodulin

increased production of cyclic AMP

When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________. into; negative into; positive out of; negative out of; positive

into; positive

When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________. into; positive out of; negative out of; positive into; negative

into; positive

What is the purpose of acetylcholinesterase on the postsynaptic membrane ________. it is an enzyme that breaks acetylcholine down into acetic acid and choline it initiates a depolarization of the postsynaptic membrane it opens voltage-gated sodium channels it closes voltage-gated calcium channels

it is an enzyme that breaks acetylcholine down into acetic acid and choline

1. Graded potentials result from the opening of ________________. ATP pumps leakage channels voltage-gated channels ligand-gated channels

ligand-gated channels

1. Graded potentials result from the opening of ________________. ATP pumps voltage-gated channels ligand-gated channels leakage channels

ligand-gated channels

Graded potentials result from the opening of ________________. -ligand-gated channels -leakage channels -voltage-gated channels -ATP pumps

ligand-gated channels

Depolarization occurs because __________. Multiple Choice more K+ diffuses into the cell than Na+ diffuses out of it more K+ diffuses out of the cell than Na+ diffuses into it more Na+ diffuses into the cell than K+ diffuses out of it more Na+ diffuses out of the cell than K+ diffuses into it both Na+ and K+ diffuse into the cell

more Na+ diffuses into the cell than K+ diffuses out of it

Assume in a laboratory you were able to isolate a neuron and remove the Acetylcholine receptors from the postsynaptic membrane. The substance _________________ would no longer cause facilitation of this neuron. caffeine nicotine

nicotine

Curare is a competitive ACh antagonist at ________ ACh receptors. NMDA kainate muscarinic nicotinic

nicotinic

The absolute refractory period causes action potential propagation to ___________. cease begin increase occur in both directions occur in one direction

occur in one direction

An inhibitory postsynaptic potential results from the opening of ____________________. chloride and/or sodium channels sodium and/or potassium channels potassium and/or chloride channels

potassium and/or chloride channels

Repolarization occurs because __________. -potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close -the extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value -the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level -more sodium ions diffuse into the cell than potassium ions diffuse out of it -the inactivation gates of the voltage-gated sodium ion channels begin to open and the diffusion of sodium ions decreases

potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close

Graded potentials are produced within the _______________________ segment of a neuron. -initial -receptive -transmissive -conductive

receptive

Graded potentials are produced within the _______________________ segment of a neuron. receptive transmissive conductive initial

receptive

The increase in calcium ion concentration causes ________. voltage-gated sodium channels to open voltage-gated potassium channels to open release of acetylcholine from the synaptic vesicles into the synaptic cleft a new action potential to be created that jumps across the synaptic cleft

release of acetylcholine from the synaptic vesicles into the synaptic cleft

The following information best describes the _____________ phase of an action potential. A membrane potential reading of +10 mV Inactivated voltage-gated sodium channels Open voltage-gated potassium channels repolarization resting depolarization hyperpolarization

repolarization

The following information best describes the _____________ phase of an action potential. • A membrane potential reading of +10 mV• Inactivated voltage-gated sodium channels • Open voltage-gated potassium channels repolarization resting hyperpolarization depolarization

repolarization

Degeneration of dopaminergic neurons of the nigrostriatal dopamine system may cause __________. visual disturbances drug addictions severe motor problems schizophrenia

severe motor problems

Normally, sodium and potassium leakage channels differ because ___________________. -sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell -sodium leakage channels always remain open, but potassium leakage channels must be specifically activated to open -sodium leakage channels require ATP to transport ions, but potassium leakage channels do not -sodium leakage channels are voltage gated, but potassium leakage channels are ligandgated

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

Normally, sodium and potassium leakage channels differ because ___________________. -sodium leakage channels always remain open, but potassium leakage channels must be specifically activated to open -sodium leakage channels require ATP to transport ions, but potassium leakage channels do not -sodium leakage channels are voltage-gated, but potassium leakage channels are ligand-gated -sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

Depolarization occurs because __________. -potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close -the extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value -the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level -sodium ions diffusing into the cell through ligand-gated channels is greater than potassium ions diffuse out of it -the inactivation gates of the voltage-gated sodium ion channels begin to open and the diffusion of sodium ions decreases

sodium ions diffusing into the cell through ligand-gated channels is greater than potassium ions diffuse out of it

The ability of synapses to change how they respond to stimuli is known as _______. temporal summation spatial summation synaptic plasticity EPSP

synaptic plasticity

The capacity of synapses for alteration at the molecular level is termed ________. synaptic plasticity synaptic modulation synaptic alteration synaptic capacitance

synaptic plasticity

Hyperpolarization, or after potential occurs because __________. -potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close -the extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value -the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level -more sodium ions diffuse into the cell than potassium ions diffuse out of it -the inactivation gates of the voltage-gated sodium ion channels begin to open and the diffusion of sodium ions decreases

the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level

Serotonin is synthesized from the amino acid ________. glycine serine tryptophan alanine

tryptophan