Physiology - Ch. 8 Neurons
170) The basis of neural integration is A) linear addition of postsynaptic potentials overlapping in time and space. B) command signals from central pattern generators. C) spontaneous activity in pacemaker neurons. D) the area under the curve of postsynaptic potentials overlapping in time and
Linear addition of postsynaptic potentials overlapping in time and space
152) When the neuron is at rest, which statement is true? A) The activation gate is closed. B) The inactivation gate is open. C) No Na+ crosses the membrane. D) A and B E) A and C
A and B
64) Which is/are the most common inhibitory neurotransmitter(s) of the CNS? A) GABA B) glycine C) glutamate D) A and B E) all of the above
A and B
158) When comparing action potentials to graded potentials, an important distinguishing characteristic is A) only graded potentials can undergo summation. B) only action potentials can undergo summation. C) the rate of action potentials is limited by the refractory period. D) A and C E) B and C
A and C
163) Conduction speed is (or can be) enhanced by A) myelin. B) altering extracellular sodium concentration. C) increasing the temperature. D) altering extracellular potassium concentration. E) A and C
A and C
166) Graded potentials can A) act as signals over short distances. B) act as signals over long distances. C) cause or prevent an action potential. D) A and C E) B and C
A and C
9) The enteric nervous system is a network of neurons that function in controlling A) reproduction. B) digestion. C) excretion, particularly urination. D) the skeletal system. E) the endocrine system.
Digestion
22) Clusters of nerve cell bodies in the peripheral nervous system are called A) microglia B) neuroglia C) glia D) ganglia E) nodes
Ganglia
176) Learning and memory are thought to be due to a synaptic phenomenon known as A) inhibition. B) excitation. C) modulation. D) facilitation. E) long-term potentiation
Long-term potentiation
82) If a hyperpolarizing graded potential and a depolarizing graded potential of similar magnitudes arrive at the trigger zone at the same time, what happens? A) An action potential is fired off more quickly than usual. B) Nothing. They will cancel each other out. C) The cell becomes hyperpolarized. D) The cell becomes easier to excite. E) The cell dies.
Nothing. They will cancel each other out
12) Interneurons are found A) only in the brain. B) only in the spinal cord. C) only in the CNS. D) throughout the nervous system. E) only in spinal nerves.
Only in the CNS
90) Repair of damaged neurons can be assisted by certain neurotrophic factors secreted by the A) cell body. B) axon. C) dendrites. D) Schwann cells. E) B and C
Schwann cells
8) Autonomic motor neurons are subdivided into the A) visceral and somatic divisions. B) sympathetic and parasympathetic divisions. C) central and peripheral divisions. D) visceral and enteric divisions. E) somatic and enteric divisions.
Sympathetic and parasympathetic divisions.
28) The Nernst equation predicts A) intracellular ion concentrations. B) extracellular ion concentrations C) the membrane potential resulting from all permeable ions. D) the membrane potential resulting from permeability to a single ion. E) the threshold membrane potential.
The membrane potential resulting from permeability to a single ion.
35) The total amount of neurotransmitter released at the axon terminal is directly related to A) the amplitude of the action potential. B) the length of the axon. C) the total number of action potentials. D) the amplitude of the graded potential.
The total number of action potentials
15) The collection of axons that carries information between the central nervous system and the peripheral effectors is called the A) axon hillock. B) varicosity. C) axon. D) dendrite. E) nerve.
Nerve
153) In the first phase of triggering an action potential in a neuron, Na+ ions flow in and A) trigger a negative feedback loop. B) trigger a positive feedback loop. C) activate the sodium/potassium pump. D) A and C E) B and C
Trigger a positive feedback loop
167) The following are steps involved in transmission at the cholinergic synapse. 1. Chemically regulated ion channels on the postsynaptic membrane are activated. 2. Calcium ions enter the axon terminal. 3. An action potential depolarizes the axon terminal at the presynaptic membrane. 4. Acetylcholine is released from storage vesicles by exocytosis. 5. Acetylcholine binds to receptors on the postsynaptic membrane. The correct sequence for these events is A) 4, 2, 1, 5, 3 B) 3, 2, 4, 5, 1 C) 2, 4, 1, 3, 5 D) 2, 5, 4, 1, 3 E) 1, 2, 3, 4, 5
3, 2, 4, 5, 1
69) Once the stimulus alters the receptor on the cell's membrane, what happens next? A) Ion channels open, allowing ions to enter or exit. B) The membrane permeability is altered. C) A second messenger is activated on the inside of the cell. D) Any of the above could happen next.
Any of the above could happen next
175) Presynaptic facilitation occurs when A) extracellular concentration of sodium increases. B) extracellular concentration of potassium increases. C) calcium channels in the presynaptic membrane are inhibited. D) calcium channels in the presynaptic membrane remain open longer. E) temporal summation occurs.
Calcium channels in the presynaptic membrane remain open longer
21) Anterograde and retrograde axonal transport are forms of __________ transport. A) fast B) slow C) neither of these
Fast
76) Identify the FALSE statement. A) EPSPs that reach threshold can initiate an action potential. B) The trigger zone is the integrating center of the neuron. C) IPSPs depolarize the membrane. D) All of the above are true.
IPSPs depolarize the membrane
162) Conduction occurs along an axon because A) outflow of K+ triggers the adjacent channels to open. B) inflow of Na+ triggers the adjacent channels to open. C) once Na+ enters the cell, the entire membrane depolarizes simultaneously. D) axonal transport "walks" voltage changes along the membrane
Inflow of Na+ triggers the adjacent channels to open
155) The inactivation gate A) quickly opens and closes after depolarization. B) is coupled to the movement of the activation gate, but is much slower. C) depends on a change of +100 mV from rest to be signaled to close. D) depends on a loss of Na+ permeability to be triggered. E) depends on a loss of K+ permeability to be triggered
Is coupled to the movement of the activation gate, but is much slower
66) Excitatory neurotransmitters of the CNS usually act by opening __________ channels. A) Na+ B) K+ C) Cl- D) H+ E) Ca2+
Na+
151) Identify the FALSE statement. A) Under normal conditions, all action potentials in a given cell are identical. B) Between nodes of Ranvier, signal conduction is decremental. C) The amplitude of the action potential depends on the amplitude of the graded potential that precedes it. D) The voltage-gated sodium and potassium channels begin to open at the same time. E) A, B, and D are true.
The amplitude of the action potential depends on the amplitude of the graded potential that precedes it
68) The site of information integration in the nervous system is the A) chemical synapse. B) electrical synapse. C) trigger zone. D) dendritic membrane. E) axon terminal.
Trigger zone
2) Detailed understanding of the cellular basis of signaling in the nervous system has lead to good understanding of consciousness, intelligence, and emotion. A) true B) false
False
74) In order for a synapse to be an effective means of cellular communication, slow removal or inactivation of neurotransmitter molecules from the synapse is important. A) true B) false
False
16) The region where the axon terminal meets its target cell is called the A) collateral. B) hillock. C) synapse. D) nerve. E) dendrites.
Synapse
60) A chemical synapse ALWAYS includes __________. 1. axon terminal 2. presynaptic cell 3. synaptic cleft 4. postsynaptic cell 5. dendrite A) 1, 2, 3, 4, 5 B) 1, 2, 3, 4 C) 2, 3, 4 D) 2, 3, 4, 5 E) 1, 3, 4
1,2,3,4
41) An increased threshold is associated with the __________ refractory period. A) absolute B) relative
Absolute
62) The ion necessary to initiate the release of acetylcholine into the synaptic cleft is A) sodium. B) potassium. C) calcium. D) chloride. E) zinc.
Calcium
61) Which type of synapse is most prevalent in the nervous system? A) chemical B) electrical C) mechanical D) processing E) radiative
Chemical
24) Glial cells communicate primarily using A) electrical signals. B) chemical signals. C) neurotransmitters. D) neuromodulators. E) A and B
Chemical Signals
91) The tip of an embryonic nerve cell's axon is called a A) kissing cone. B) stem tip. C) growth cone. D) growth tip. E) none of the above
Growth Cone
54) Which of the following will increase the conduction rate of action potentials? A) Increase the diameter of the axon, decrease the resistance of the axon membrane to ion leakage. B) Increase the diameter of the axon, increase the resistance of the axon membrane to ion leakage. C) Decrease the diameter of the axon, decrease the resistance of the axon membrane to ion leakage. D) Decrease the diameter of the axon, increase the resistance of the axon membrane to ion leakage.
Increase the diameter of the axon, increase the resistance of the axon membrane to ion leakage
156) During the relative refractory period, an initial threshold-level depolarization is usually not sufficient to trigger an action potential. Why? A) Only some Na+ channels have returned to their resting position. B) K+ channels are still open, so Na+ entry is offset by K+ loss. C) Only a few K+ channels have returned to their resting position. D) The statement is incorrect; a threshold-level depolarization always triggers an action potential. E) A and B
A and B
31) The resting membrane potential results from A) uneven distribution of ions across the cell membrane. B) differences in membrane permeability to Na+ and K+. C) activity of the sodium/potassium pump. D) A and B E) none of the above
A and B
4) Information coming into the central nervous system is transmitted along __________ neurons. A) afferent B) sensory C) efferent D) A and B E) B and C
A and B
52) Ion concentrations are first significantly affected after __________ action potential(s). A) one B) a few dozen C) a few hundred D) a few thousand E) a few million
A few thousand
79) When two or more graded potentials arrive at the trigger zone, which of the following could happen? A) An excitatory and inhibitory signal can cancel each other out. B) Two excitatory stimuli may be additive, and summation could occur. C) Two inhibitory stimuli may be additive, resulting in lower excitability. D) A and B E) A, B, and C
A, B, and C
83) Temporal summation refers to A) the temporal lobe of the brain integrating neuronal interaction. B) multiple graded potentials originating from different locations simultaneously. C) additional graded potential(s) arriving before previous ones have ceased. D) suprathreshold potentials triggering action potentials that are extra large. E) All of the above accurately describe temporal summation.
Additional graded potential(s) arriving before previous ones have ceased
40) Choose all the items that are incorrectly matched. A) activation gate - closed at rest B) inactivation gate - open at rest C) inactivation gate - opens during repolarization D) activation gate - opens during depolarization E) All of the above are incorrectly matched
All of the above are incorrectly matched
78) Inhibitory postsynaptic potentials (IPSPs ) A) result in local depolarizations. B) result in local hyperpolarizations. C) increase membrane permeability to sodium ions. D) prevent the escape of potassium ions. E) prevent the escape of calcium ions.
Result in local hyperpolarizations
159) When more action potentials arrive at the axon terminal, how are neurotransmitters affected? A) More molecules are released into the synapse. B) Different molecules are released into the synapse. C) Fewer molecules are released into the synapse. D) There is no effect—all signals are identical
More molecules are released into the synapse
173) Tetrodotoxin is a toxin that blocks voltage-gated sodium channels. What effect does this substance have on the function of neurons? A) Neurons depolarize more rapidly. B) Action potentials lack a repolarization phase. C) The absolute refractory period is shorter than normal. D) The neuron is not able to propagate action potentials. E) The toxin does not interfere with neuron function because the voltage-regulated sodium channels would still function.
The neuron is not able to propagate action potentials
172) Tom's father suffers a stroke that leaves him partially paralyzed on his right side. What type of glial cell would you expect to find in increased numbers in the damaged area of the brain that is affected by the stroke? A) astrocytes B) Schwann cells C) oligodendrocytes D) microglia
Microglia
26) These glial cells act as scavengers. A) Schwann cells B) astrocytes C) microglia D) oligodendrocytes E) ependymal cells
Microglia
81) Spatial summation refers to A) electrical signals reaching neurons from outer space. B) multiple graded potentials arriving at one location simultaneously. C) repeated graded potentials reaching the trigger zone one after the other. D) suprathreshold potentials triggering action potentials that are extra large. E) all of the above
Multiple graded potentials arriving at one location simultaneously
37) The rising phase of the action potential is due to A) Na+ flow into the cell. B) Na+ flow out of the cell. C) K+ flow out of the cell. D) K+ flow into the cell. E) B and D
Na+ flow into the cell
58) The major determinant of the resting potential of all cells is A) Ca2+ concentration in the blood and interstitial fluid. B) Na+ concentration in the blood and interstitial fluid. C) K+ gradient between the blood and interstitial fluid. D) K+ concentration inside cells. E) Na+ concentration inside cells.
K+ gradient between the blood and interstitial fluid
11) The cell body of neurons is generally A) 90% of the cell volume. B) 50% of the cell volume. C) 10% of the cell volume. D) found in the same position on every neuron.
10% of the cell volume
56) Graded potentials may A) initiate an action potential. B) depolarize the membrane to the threshold voltage. C) hyperpolarize the membrane. D) be called EPSPs or IPSPs. E) All of the above are true.
All of the above are true
49) When voltage-gated Na+ channels of a resting neuron open, A) Na+ enters the neuron. B) Na+ leaves the neuron. C) the neuron depolarizes. D) A and C E) B and C
A and C
42) The absolute refractory period of an action potential A) ensures one-way travel down an axon. B) allows a neuron to ignore a second signal sent that closely follows the first. C) prevents summation of action potentials. D) A and B E) A, B, and C
A, B, and C
33) The channelopathy known as QT syndrome, is a result of mutation in __________ channels. A) sodium B) potassium C) calcium D) chloride E) A, B, or C
A, B, or C
59) The term hyperkalemia specifically indicates too much potassium in which fluid compartment? A) blood B) intracellular C) interstitial D) extracellular E) all of the above
Blood
89) A damaged neuron has a better chance of survival and repair if the __________ is/are undamaged. A) cell body B) axon C) dendrites D) Schwann cells E) B and C
Cell body
6) The brain and spinal cord together compose the A) central nervous system. B) autonomic division system. C) somatic motor division of the nervous system. D) peripheral nervous system. E) visceral nervous system.
Central Nervous System
67) Which of the following is NOT a known drug effect on synaptic function? A) interfere with neurotransmitter synthesis B) alter the rate of neurotransmitter release C) prevent neurotransmitter inactivation D) prevent neurotransmitter binding to receptors E) change the type of neurotransmitter found in the synaptic vesicle
Change the type of neurotransmitter found in the synaptic vesicle
46) Voltage-regulated channels are located A) within the cytosol. B) in the membranes of dendrites. C) in the membranes of axons. D) on the neuron cell body. E) all of the above
In the membranes of axons
147) If the resting axon's membrane becomes more permeable to potassium ions, A) the inside of the membrane will become more positively charged. B) the membrane will depolarize more rapidly. C) it will take a stimulus of larger magnitude to initiate an action potential. D) the membrane will become hyperpolarized. E) the hyperpolarization at the end of the action potential will not occur.
It will take a stimulus of larger magnitude to initiate an action potential
150) How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated? A) It would be longer than normal. B) It would be shorter than normal. C) It would be the same whether the channels remained inactivated or not. D) none of the above
It would be longer than normal
38) The falling phase of the action potential is due primarily to A) Na+ flow in the cell. B) Na+ flow out of the cell. C) K+ flow out of the cell. D) K+ flow into the cell. E) B and D
K+ flow out of the cell
85) When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs? A) spatial summation B) temporal summation C) inhibition of the impulse D) hyperpolarization E) decrease in speed of impulse transmission
Temporal summation
45) All of the following must occur before a second action potential can begin, EXCEPT A) the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments. B) the Na+ inactivation gate must open and the Na+ activation gate must close. C) the absolute refractory period must occur. D) A and B E) none of the above
The Na+ and K+ ions that moved in/out of the cell must move back to their original compartments.
30) What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT? A) the electrical charges of the ions B) the permeabilities of the ions C) the solubilities of the ions D) the sizes of the ions E) the temperature
The permeabilities of the ions
36) Which of the following is the location where action potentials originate? A) dendrites B) trigger zone C) axon hillock D) initial segment E) synapse
Trigger Zone
20) The term axonal transport refers to A) the release of neurotransmitter molecules from the axon. B) the transport of microtubules to the axon for structural support. C) vesicle transport of proteins and organelles down the axon. D) the movement of the axon terminal to synapse with a new postsynaptic cell. E) none of the above
Vesicle transport of proteins and organelles down the axon.
55) Which of the following does NOT influence the time necessary for a nerve impulse to be conveyed by a particular neuron? A) length of the axon B) presence or absence of a myelin sheath C) diameter of the axon D) presence or absence of nodes of Ranvier E) whether axon is sensory or motor
Whether axon is sensory or motor
19) Neurotransmitters are released from the A) dendrites. B) axon terminals. C) collaterals. D) axon hillock. E) synapse.
Axon terminals
53) Action potentials occur in the membrane of A) dendrites. B) cell bodies. C) axons. D) A and C E) B and C
Axons
10) In general, the nervous system is composed of which two types of cells? 1) motor 2) neurons 3) sensory 4) glial 5) associative
2 and 4
29) Which is the correctly written Nernst equation? A) 61/z × log [ion]out / [ion]in B) 61/z × log [ion]in / [ion]out C) log 61/z × [ion]in / [ion]out D) log 61/z × [ion]out / [ion]in
61/z × log [ion]out / [ion]in
3) Neurotransmitter is stored and released from A) axon terminals. B) axon varicosities. C) dendritic spines. D) cell bodies. E) A and B
A and B
43) During the relative refractory period, __________ gates are open. A) sodium B) potassium C) calcium D) chloride E) A and B
A and B
17) The axon is connected to the cell body by the A) myelin sheath. B) axon terminal. C) collaterals. D) axon hillock. E) synapse.
Axon Hillock
148) If the sodium-potassium pumps in the cell membrane of a neuron fail to function, over time A) the extracellular concentration of potassium ion will increase. B) the intracellular concentration of sodium ion will increase. C) the membrane resting potential will become more positive than normal. D) all of the above
All of the above
23) Glial cells A) provide structural and metabolic support. B) guide neurons during growth and repair. C) help maintain homeostasis of the brain's extracellular fluid. D) A and C E) all of the above
All of the above
48) The all-or-none principle states that A) all stimuli will produce identical action potentials. B) all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude. C) the greater the magnitude of the stimuli, the greater the intensity of the action potential. D) only sensory stimuli can activate action potentials. E) only motor stimuli can activate action potentials
All stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude
57) Some neurotoxins work essentially the same way as some local anesthetics, which is to A) inactivate the enzyme that destroys the neurotransmitter. B) bind to Na+ channels and inactivate them. C) prevent depolarization by blocking Na+ entry into the cell. D) A and B E) B and C
B and C
80) Presynaptic facilitation makes a pathway A) less likely to be in use, through hyperpolarization of selected neurons. B) more likely to be in use, through depolarization of selected neurons. C) capable of alteration through training and conditioning. D) A and C E) B and C
B and C
25) Myelin is formed by A) axons. B) ependymal cells. C) Schwann cells. D) oligodendrocytes. E) C and D
C and D
77) An excitatory postsynaptic potential (EPSP) A) depolarizes a neuron, decreasing the likelihood of an action potential. B) hyperpolarizes a neuron, decreasing the likelihood of an action potential. C) depolarizes a neuron, increasing the likelihood of an action potential. D) hyperpolarizes a neuron, increasing the likelihood of an action potential.
Depolarizes a neuron, increasing the likelihood of an action potential
145) These glial cells may be a source of treatment for neural degenerative disorders. A) Schwann cells B) astrocytes C) microglia D) oligodendrocytes E) ependymal cells
Ependymal cells
27) These glial cells may contribute to Lou Gehrig's disease. A) Schwann cells B) astrocytes C) microglia D) oligodendrocytes E) ependymal cells
Microglia
44) In order to signal a stronger stimulus, action potentials become A) higher in amplitude. B) more frequent. C) longer lasting. D) A and B E) A and C
More frequent
39) The point during an action potential when the inside of the cell has become more positive than the outside is known as the A) depolarization. B) rising phase. C) falling phase. D) overshoot. E) peak.
Overshoot
5) The afferent and efferent axons together form the A) central nervous system. B) autonomic division system. C) somatic motor division of the nervous system. D) peripheral nervous system. E) visceral nervous system.
Peripheral Nervous System
88) The rearrangement of connections at synapses, which occurs throughout life, is termed A) elasticity. B) intelligence. C) plasticity. D) senility. E) synchronicity.
Plasticity
32) Which ion(s) is/are higher in concentration inside the cell compared to outside? A) potassium B) sodium C) chloride D) calcium E) more than one of the above
Potassium
1) The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called A) protrusions. B) processes. C) prostheses. D) projections.
Processes
47) The sodium-potassium exchange pump A) must re-establish ion concentrations after each action potential. B) transports sodium ions into the cell during depolarization. C) transports potassium ions out of the cell during repolarization. D) moves sodium and potassium in the direction of their chemical gradients. E) requires ATP to function.
Requires ATP to function
149) Inactivation of the sodium channel is possible because A) the activation gate becomes insensitive to stimuli. B) the extracellular concentration of sodium decreases. C) it is inactivated by the positive potential that develops during the action potential. D) there is more than one gate that can close the channel.
There is more than one gate that can close the channel
157) The following are the main steps in the generation of an action potential. 1. sodium channels are inactivated 2. voltage-regulated potassium channels open and potassium moves out of the cell, initiating repolarization 3. sodium channels regain their normal properties 4. a graded depolarization brings an area of an excitable membrane to threshold 5. a temporary hyperpolarization occurs 6. sodium channel activation occurs 7. sodium ions enter the cell and further depolarization occurs The proper sequence of these events is A) 4, 6, 7, 3, 2, 5, 1. B) 4, 6, 7, 1, 2, 5, 3. C) 6, 7, 4, 1, 2, 3, 5. D) 2, 4, 6, 7, 1, 3, 5. E) 4, 2, 5, 6, 7, 3, 1.
4, 6, 7, 1, 2, 5, 3
168) Arrange the following events in the proper sequence. 1. Efferent neuron reaches threshold and fires an action potential. 2. Afferent neuron reaches threshold and fires an action potential. 3. Effector organ responds by performing output. 4. Integrating center reaches decision about response. 5. Sensory organ detects change in the environment. A) 2, 3, 5, 1, 4 B) 5, 2, 4, 1, 3 C) 5, 1, 4, 2, 3 D) 5, 3, 4, 2, 1 E) 3, 1, 4, 2, 5
5, 2, 4, 1, 3
174) Inhibition of neural activity can result from A) presynaptic events. B) postsynaptic events. C) A and B
A and B
72) In response to binding a neurotransmitter, a postsynaptic cell can A) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials. B) close ion channels via G proteins and second messenger systems, producing slow responses. C) regulate protein synthesis and affect the metabolic activities of the postsynaptic cell. D) A and C E) A, B, and C
A,B, and C
70) Once the action potential reaches the axon terminal, what happens next? A) exocytosis of a neurocrine B) release of the neurotransmitter into the synaptic cleft C) release of a neurohormone into the blood D) Any of the above could happen next.
Any of the above could happen next
7) Exocrine glands, smooth muscles, and cardiac muscles are controlled by the A) central nervous system. B) autonomic nervous system. C) somatic motor division. D) peripheral nervous system. E) enteric nervous system.
Autonomis Nervous System
165) The primary problem in hyperkalemia is that A) neurons are harder to excite because their resting potential is hyperpolarized. B) neurons are hyperexcitable because their resting potential is closer to threshold. C) neurons respond too quickly to smaller graded potentials. D) A and C E) B and C
B and C
87) During childhood, growth and development of the brain PRIMARILY occurs by increasing A) neuron numbers. B) neuron size. C) number of dendrites and synapses. D) A and B E) B and C
B and C
51) In the membrane of a resting nerve cell, when chemically gated Cl- channels open, A) Cl- ions enter the cell. B) Cl- ions leave the cell. C) the cell becomes depolarized. D) A and C E) B and C
Cl- ions enter the cell
65) Inhibitory neurotransmitters of the CNS act by opening __________ channels. A) Na+ B) Cl- C) K+ D) Ca2+ E) Cl- or K+
Cl- or K+
34) Ion channel inactivation is A) closing of the channel in response to decrease in the stimulus. B) closing of the channel even when the stimulus continues. C) any type of channel closing. D) none of the above
Closing of the channel even when the stimulus continues.
18) Branches that sometimes occur along the length of an axon are called A) dendrites. B) axon terminals. C) collaterals. D) axon hillocks. E) synapses.
Collaterals
86) The pattern of synaptic connectivity where a large number of presynaptic neurons provide input to a single postsynaptic neuron, is known as A) divergence. B) convergence. C) integration. D) saltatory conduction. E) potentiation.
Convergence
14) The structure on the neuron that transmits electrical signals to trigger the release of neurotransmitter is the A) axon hillock. B) varicosity. C) axon. D) dendrite. E) nerve.
Dendrite
13) The multiple thin, branched structures on a neuron whose main function is to receive incoming signals are the A) cell bodies. B) axons. C) dendrites. D) somata. E) none of the above
Dendrites
143) Microvilli are present on cells that, because of their function, benefit from an increased membrane surface area. Which structure(s) on a neuron provide a comparable benefit? A) cell body B) dendrites C) axon D) varicosities E) collaterals
Dendrites
144) A home satellite dish receives signals from a satellite, allowing your television to display TV shows. Which part of a neuron is analogous to the satellite dish? A) cell body B) dendrites C) axon D) varicosities E) collaterals
Dendrites
146) In terms of embryonic origin, neurons are most closely related to __________ cells. A) skeletal muscle B) cardiac muscle C) connective tissue D) epithelial
Epithelial
73) The neurotransmitter thought to be involved in learning and memory is A) norepinephrine. B) glutamate. C) acetylcholine. D) GABA. E) glycine.
Glutamate
50) When voltage-gated K+ channels of a resting neuron open, A) K+ enters the neuron. B) K+ leaves the neuron. C) the neuron depolarizes. D) A and C E) B and C
K+ leaves the neuron
75) Which is NOT a neuroeffector junction? The junction between a neuron and a(n) A) skeletal muscle. B) smooth muscle. C) endocrine gland. D) exocrine gland. E) neuron.
Neuron
160) When more action potentials arrive at the axon terminal, how is the postsynaptic cell affected? A) Neurotransmitter release increases, but does not change the graded potentials that follow. B) Neurotransmitter release does not change, thus the postsynaptic cell behaves the same way it always behaves. C) Neurotransmitter release increases, thereby increasing the frequency or magnitude of graded potentials in the postsynaptic cell. D) Neurotransmitter release does not change, but voltages applied to the postsynaptic cell increase.
Neurotransmitter release increases, thereby increasing the frequency or magnitude of graded potentials in the postsynaptic cell
84) When multiple, possibly even conflicting signals reach a neuron, the neuron evaluates the signals and may respond or not. This property is called A) temporal summation. B) spatial summation. C) postsynaptic integration. D) graded potentials. E) EPSPs.
Postsynaptic integration
164) When sodium channels open during an action potential, the opening is caused by A) binding of sodium ions. B) binding of potassium ions. C) presence of calcium. D) presence positive charge.
Presence positive charge
63) To increase the amount of neurotransmitter released onto a postsynaptic cell, the presynaptic cell would have to A) send action potentials with higher voltage (higher amplitude). B) send action potentials with longer durations. C) send action potentials with higher frequency. D) do nothing; no change is possible since the all-or-none law is in effect.
Send action potentials with higher frequency
71) Calcium is important in the synapse because it A) is necessary for acetylcholine synthesis. B) signals the exocytosis of the neurotransmitter. C) binds to receptors on the postsynaptic cell, opening ion channels, and triggering graded potentials. D) leaves the axon terminal, hyperpolarizing the cell.
Signals the exocytosis of the neurotransmitter
171) Caffeine, nicotine, and alcohol all have effects on A) action potential conduction. B) long-term potentiation. C) synaptic activity. D) neurotransmitter degradation. E) neurotransmitter reuptake.
Synaptic activity
154) What stops the rising phase of the action potential? A) The K+ gate closes. B) The Na+ activation gate opens. C) The Na+ inactivation gate closes. D) The Na+ inactivation gate opens. E) The sodium activation gate closes.
The Na+ inactivation gate closes
169) How would blocking retrograde transport in an axon affect the activity of a neuron? A) The neuron would not be able to produce neurotransmitters. B) The neuron would not be able to produce action potentials. C) The cell body would not be able to export products to the axon terminals. D) The cell body would not be able to respond to changes in the distal end of the axon. E) The neuron would be unable to depolarize when stimulated.
The cell body would not be able to respond to changes in the distal end of the axon
161) If an electrode is placed in the middle of a resting axon and an above-threshold voltage is applied, action potentials A) will not occur. B) will start at that point and proceed only toward the axon terminal. C) will start at that point and proceed only toward the cell body. D) will start at that point and travel in both directions in the axon.
Will start at that point and travel in both directions in the axon
