Chapter 08 test bank
30. Anterograde and retrograde axonal transport are forms of ____ transport. A.fast B. slow C.neither of these.
A. Fast
153) originate(s) at the trigger zone
A. action potential
16. The axon is connected to the cell body by the A. Synapse B. Axon Hillock C. Axon terminal D. Collaterals E. Myelin Sheath
B. Axon Hillock
71) The falling phase of the action potential is due mainly to A) Na+ flow out of the cell and K+ flow into the cell. B) Na+ flow out of the cell only. C) K+ flow out of the cell only. D) Na+ flow in the cell only. E) K+ flow into the cell only.
C. K+ flow out of the cell only
61) A chemical synapse ALWAYS includes which of the following? 1. axon terminal 2. presynaptic cell 3. synaptic cleft 4. postsynaptic cell 5. dendrite A) 1, 3, 4 B) 1, 2, 3, 4, 5 C) 2, 3, 4, 5 D) 1, 2, 3, 4 E) 2, 3, 4
D. 1,2,3,4
146) supported by satellite cells
cell bodies
161) receive most of the incoming synapses
dendrites
169) occupy the least amount of cell volume
dendrites
170) contribute most to membrane surface area of cell
dendrites
171) where most graded potentials originate
dendrites
172) cells that are a source of neural stem cells cells
ependymal cells
173) originate(s) on dendrites and cell bodies
graded potential
127) A ________ is a compound that influences a postsynaptic cell's response to a neurotransmitter
neuromodulator
174) cells in the CNS that form myelin
oligodendrocytes
168) Schwann cells
peripheral nervous system
139) A change in the conditions in the axon terminal can cause a change in the environment of the cell body as a result of ________.
retrograde transport
118) An influx of Na+ ions depolarizes the membrane of an axon.
true
122) The absolute refractory period is important in one-way direction of action potentials.
true
132) If the graded potential increases in amplitude, then the frequency of the action potentials fired also increases.
true
134) The potential difference across a membrane or other barrier is a measure of the ________ across the barrier.
voltage
123) Name the two factors that influence the membrane potential.
1.the concentration gradients of ions across the membrane. 2.the membrane permeability to those ions
149) location of voltage-gated ion channels involved in action potentials
A) axons.
166) can result from influx of sodium
A) both
162) satellite cells
A) peripheral nervous system
14. Neurotransmitters are released from the A.axon terminals B.dendrites C.Synapses D.collaterals E.axon hillocks.
A. Axon terminals
33. the ion necessary to initiate the release of acetylcholine into the synaptic cleft is A) calcium. B) potassium. C) chloride. D) sodium. E) zinc.
A. Calcium
38) Branches that sometimes occur along the length of an axon are called A) collaterals. B) dendrites. C) axon terminals. D) axon hillocks. E) synapses.
A. Collaterals
53) In the first phase of initiating an action potential in a neuron, Na+ ions flow in and A) create a positive feedback loop. B) activate the sodium/potassium pump. C) create a positive feedback loop and activate the sodium/potassium pump. D) create a negative feedback loop. E) create a negative feedback loop and activate the sodium/potassium pump.
A. Create a positive feedback loop
97) Identify the FALSE statement. A) IPSPs depolarize the membrane. B) The trigger zone is the integrating center of the neuron. C) EPSPs that reach threshold can initiate an action potential. D) All of the statements are true.
A. IPSPs depolarize the membrane
79) The major determinant of the resting potential of all cells is A) K+ gradient between the blood and interstitial fluid. B) Na+ concentration inside cells. C) Ca2+ concentration in the blood and interstitial fluid. D) Na+ concentration in the blood and interstitial fluid. E) K+ concentration inside cells
A. K+ gradient between the blood and interstitial fluid
98) When voltage-gated K+ channels of a resting neuron open, A) K+ leaves the neuron. B) K+ enters the neuron and the neuron depolarizes. C) the neuron depolarizes. D) K+ leaves the neuron and the neuron depolarizes. E) K+ enters the neuron.
A. K+ leaves the neuron
48) To increase the amount of neurotransmitter released onto a postsynaptic cell, the presynaptic cell would have to A) send action potentials with higher frequency. B) send action potentials with higher voltage (higher amplitude). C) send action potentials with longer durations. D) do nothing; no change is possible since the all-or-none law is in effect.
A. Send action potentials with higher frequencies.
85) Tetrodotoxin is a toxin that blocks voltage-gated sodium channels. What effect does this substance have on the function of neurons? A) The neuron is not able to transmit action potentials. B) Action potentials lack a repolarization phase. C) Neurons depolarize more rapidly. D) The toxin does not interfere with neuron function because the voltage-regulated sodium channels would still function. E) The absolute refractory period is shorter than normal.
A. The neuron is not able to transmit action potentials
86) Ion concentrations are first significantly affected after ________ action potential(s). A) a few thousand B) a few million C) a few hundred D) a few dozen E) one
A. a few thousand
1) Exocrine glands, smooth muscles, and cardiac muscles are controlled by the A) autonomic division. B) enteric nervous system. C) peripheral nervous system. D) central nervous system. E) somatic motor division.
A. autonomic division
87) Which is the most common location where action potentials start in efferent neurons? A) axon hillock B) synaptic bouton C) synaptic cleft D) dendrites E) cell body
A. axon hillock.
45) Action potentials are mainly associated with the membranes of A) axons only. B) dendrites and axons. C) cell bodies and axons. D) dendrites only. E) cell bodies only.
A. axons only
37. A damaged neuron has a better chance of survival and repair if the ________ is/are undamaged. A) cell body B) dendrites C) axon D) axon and dendrites E) Schwann cells
A. cell body
49) Which type of synapse is most common in the nervous system? A) chemical B) processing C) mechanical D) electrical E) radiative
A. chemical
5) Glial cells communicate primarily using A) chemical signals only. B) electrical signals only. C) neuromodulators only. D) neurohormones only. E) electrical signals and chemical signals.
A. chemical signals only
69) Ion channel inactivation is A) closing of the channel even when the stimulus continues. B) any type of channel closing. C) closing of the channel in response to decrease in the stimulus. D) None of the answers are correct.
A. closing of the channel even when the stimulus continues
76) The pattern of synaptic connectivity where a large number of presynaptic neurons provide input to a single postsynaptic neuron, is known as A) convergence. B) divergence. C) saltatory conduction. D) integration. E) potentiation.
A. convergence.
67) Microvilli are present on cells that benefit from an increased membrane surface area for their function. Which structure(s) on a neuron provide a comparable benefit? A) dendrites B) collaterals C) varicosities D) cell body E) axon
A. dendrites
84) Conduction occurs along an axon because A) entry of Na+ stimulates the adjacent channels to open. B) once Na+ enters the cell, the entire membrane depolarizes simultaneously. C) axonal transport "walks" voltage changes along the membrane. D) exit of K+ stimulates the adjacent channels to open.
A. entry of Na+ stimulates the adjacent channels to open.
23) In terms of embryonic origin, neurons are most closely related to ________ cells. A) epithelial B) cardiac muscle C) connective tissue D) skeletal muscle
A. epithelial
113) Clusters of nerve cell bodies in the peripheral nervous system are called A) ganglia. B) neuroglia. C) microglia. D) nodes. E) glia.
A. ganglia
42) The neurotransmitter thought to be involved in learning and memory is A) glutamate. B) acetylcholine. C) glycine. D) GABA. E) norepinephrine.
A. glutamate
106) These glial cells act as scavengers. A) microglia B) astrocytes C) oligodendrocytes D) ependymal cells E) Schwann cells
A. microglia
65) In order to signal a stronger stimulus, action potentials become A) more frequent only. B) higher in amplitude and more frequent. C) higher in amplitude only. D) higher in amplitude and longer-lasting. E) longer-lasting only.
A. more frequent only
73) Spatial summation refers to A) multiple graded potentials arriving at one location. B) electrical signals reaching neurons from outer space. 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 answers are correct.
A. multiple graded potentials arriving at one location.
15. The collection of axons that carries information between the central nervous system and the peripheral effectors is called the A.nerve B.dendrite C.Varicosity D.ganglion
A. nerve
62) When more action potentials arrive at the axon terminal, how is a postsynaptic neuron affected? A) Neurotransmitter release increases, increasing the frequency or magnitude of graded potentials in the postsynaptic neuron. B) Neurotransmitter release does not change, but voltages in the postsynaptic neuron increase. C) Neurotransmitter release increases, but does not change the graded potentials in postsynaptic neurons. D) Neurotransmitter release does not change, and the postsynaptic neuron behaves the same way it always behaves.
A. neurotransmitter release increases, increasing the frequency or magnitude of graded potentials in the postsynaptic neuron.
32) Inhibitory postsynaptic potentials (IPSPs) A) result in hyperpolarizations. B) decrease potassium ion exit from cells. C) decrease calcium ion exit from cells. D) result in depolarizations. E) increase membrane permeability to sodium ions.
A. result in hyperpolarizations
81) Calcium is important in the synapse because it A) signals the exocytosis of the neurotransmitter. B) is necessary for acetylcholine synthesis. C) binds to receptors on the postsynaptic cell, opening ion channels, and triggering graded potentials. D) leaves the axon terminal, hyperpolarizing the cell.
A. signals the exocytosis of the neurotransmitter.
116) What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT? A) the permeabilities of the ions B) the solubilities of the ions C) the temperature D) the sizes of the ions E) the electrical charges of the ions
A. the permeabilities of the ions.
109) Which does NOT influence the time necessary for a nerve impulse to be conducted by a neuron? A) whether axon is sensory or motor B) length of the axon C) diameter of the axon D) presence or absence of nodes of Ranvier E) presence or absence of a myelin sheath
A. whether axon is sensory or motor.
12. Tiering's father suffered 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.Microglia b.Oligodendrocytes C.Astrocytes D.Schwann Cells
A.microglia
6) When multiple, possibly even conflicting signals reach a neuron, the neuron evaluates the signals and may respond or not. This property is called A) postsynaptic integration. B) temporal summation. C) graded potentials. D) spatial summation. E) EPSPs.
A.postsynaptic integration
96) The sodium-potassium exchange pump A) requires ATP to function. B) moves sodium and potassium in down their chemical gradients. C) transports sodium ions into the cell during depolarization. D) must re-establish ion concentrations after each action potential. E) transports potassium ions out of the cell during repolarization.
A.requires ATP to function
148) require(s) a threshold stimulus to occur
B) action potential
163) microglia
B) central nervous system
164) ependymal cells
B) central nervous system
165) oligodendrocytes
B) central nervous system
80) The cell body of neurons is about A) 90% of the cell volume. B) 10% of the cell volume. C) 50% of the cell volume. D) found in the same position on every neuron.
B. 10% of the cell volume
82) In general, the nervous system is made up of which two types of cells? 1. motor 2. neurons 3. sensory 4. glia 5. associative A) 3and5 B) 2and4 C) 1and3 D) 1and2 E) 3and4
B. 2and4
99) In order for a synapse to be an effective means of cellular communication, removal of neurotransmitter molecules from the synapse is important. A) True B) False
B. False
90) Which will best increase the conduction rate of action potentials? A) Decrease 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, increase the resistance of the axon membrane to ion leakage. D) 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.
63) When more action potentials arrive at the axon terminal, how are neurotransmitters affected? A) Fewer molecules are released into the synapse. B) More molecules are released into the synapse. C) Different molecules are released into the synapse. D) There is no effect-all signals are identical.
B. More molecules are released into the synapse
72) Which is the main inhibitory neurotransmitter in the brain? A) GABA B) NMDA receptors C) glutamate D) AMPA receptors E) All of the answers are correct.
B. NMDA receptors.
29) Excitatory neurotransmitters of the CNS usually act by opening ________ channels. A) K+ B) Na+ C) H+ D) Cl-
B. Na+
27) When voltage-gated Na+ channels of a resting neuron open, A) Na+ enters the neuron. B) Na+ enters the neuron and the neuron depolarizes. C) Na+ leaves the neuron. D) the neuron depolarizes. E) Na+ leaves the neuron and the neuron depolarizes.
B. Na+ enters the neuron ant the neuron depolarizes.
25) When sodium channels open during an action potential, the opening is caused by A) binding of potassium ions. B) presence of positive charge. C) presence of calcium. D) binding of sodium ions.
B. Presence of positive charge
39) The enteric nervous system is a network of neurons that function in controlling A) excretion, particularly urination. B) digestion. C) the skeletal system. D) the endocrine system. E) reproduction.
B. digestion
100) If the resting axon's membrane becomes more permeable to potassium ions, A) the hyperpolarization at the end of the action potential will not occur. B) it will take a stimulus of larger magnitude to initiate an action potential. C) the inside of the membrane will become more positively charged. D) the membrane will depolarize more rapidly.
B. it will take a stimulus of larger magnitude to initiate an action potential.
77) Inhibition of neural activity can result from A) postsynaptic events only. B) presynaptic events and postsynaptic events. C) presynaptic events only.
B. presynaptic events and postsynaptic events.
151) cells in the PNS that form myelin
B. schwann cells
9) How would blocking retrograde transport in an axon affect the activity of a neuron? A) The neuron would not be able to produce action potentials. B) The cell body would not be able to respond to changes in the distal end of the axon. C) The neuron would be unable to depolarize when stimulated. D) The neuron would not be able to produce neurotransmitters. E) The cell body would not be able to transport products to the axon terminals.
B. the cell body would not be able to respond to changes in the distal end of the axon.
78) The resting membrane potential results from A) differences in membrane permeability to ions only. B) uneven distribution of ions across the cell membrane and differences in membrane permeability to ions. C) activity of the sodium/potassium pump only. D) uneven distribution of ions across the cell membrane only. E) None of the answers are correct.
B. uneven distribution of ions across the cell membrane and differences in membrane permeability to ions.
13. The afferent and efferent neurons together form the A.somatic motor division B. Peripheral nervous system C.Central Nervous System D.Visceral nervous system. E.Autonomic Division.
B.Peripheral Nervous system
56) Repair of damaged neurons can be assisted by certain neurotrophic factors secreted by the A) dendrites only. B) Schwann cells only. C) cell body only. D) axon only. E) axon and dendrites.
B.Schwann cells only
21. The inactivation gate A) depends on a change of +100 mV from rest to be signaled to close. B) is coupled to the movement of the activation gate, but is much slower. C) quickly opens and closes after depolarization. D) depends on a loss of K+ permeability to be triggered. E) depends on a loss of Na+ permeability to be triggered.
B.is coupled to the movement of the activation gate, but is much slower.
47) Which is the correctly written Nernst equation? A) log 61/z × [ion]in / [ion]out C) 61/z × log [ion]out / [ion]in B) log 61/z × [ion]out / [ion]in D) 61/z × log [ion]in / [ion]out
C) 61/z × log [ion]out / [ion]in
105) The following are the main steps in the generation of an action potential: 1. sodium channels are closed 2. more voltage-regulated potassium channels open and potassium moves out of the cell, initiating repolarization 3. sodium channels return to their resting properties 4. a graded depolarization brings depolarization to threshold 5. a temporary hyperpolarization occurs 6. sodium channels open 7. sodium ions enter the cell and further depolarization occurs The proper sequence of these events is A) 4, 2, 5, 6, 7, 3, 1. B) 4, 6, 7, 3, 2, 5, 1. C) 4, 6, 7, 1, 2, 5, 3. D) 2, 4, 6, 7, 1, 3, 5. E) 6, 7, 4, 1, 2, 3, 5.
C. 4,6,7,1,2,5,3
43) The rising phase of the action potential is due to A) K+ flow into the cell only. B) Na+ flow out of the cell only. C) Na+ flow into the cell only. D) Na+ flow out of the cell and K+ flow into the cell. E) K+ flow out of the cell only.
C. Na+ flow into the cell only
68) Which ion(s) is/are higher in concentration inside the cell compared to outside? A) sodium B) calcium C) potassium D) chloride E) More than one of the answers is correct.
C. Potassium
19. Autonomic motor neurons are subdivided into the A) visceral and enteric branches. B) visceral and somatic branches. C) sympathetic and parasympathetic braches. D) somatic and enteric branches. E) central and peripheral branches.
C. Sympathetic and parasympathetic branches.
41) The region where the axon terminal meets its target cell is called the A) dendrites. B) axon hillock. C) synapse. D) nerve. E) collateral.
C. Synapse
35) All of the following must occur before a second action potential can begin, EXCEPT A) the absolute refractory period must occur. B) the Na+ inactivation gate must open and the Na+ activation gate must close. C) the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments. D) the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments; the Na+ inactivation gate must open; and the Na+ activation gate must close. E) None of the answers are correct.
C. The Na+ and K+ ions that moved in/out of the cell must move back to their original compartments.
26. The site of information integration in the nervous system is the A. axon terminal B. Electrical synapse C. Trigger zone D. Chemical Synapse E. Dendritic membrane
C. Trigger zone
102) Choose the items that are correctly matched. A) inactivation gate - closed at rest B) inactivation gate - closed during repolarization C) activation gate - opens during depolarization D) activation gate - open at rest E) All of the answers are incorrectly matched.
C. activation gate-opens during depolarization
2) The all-or-none principle states that A) only sensory stimuli can activate action potentials. B) the greater the magnitude of the stimuli, the greater the intensity of the action potential. C) all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude. D) only motor stimuli can activate action potentials. E) all stimuli will produce identical action potentials.
C. all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude.
112) Neurotransmitter is stored and released from A) dendritic spines only. B) axon terminals only. C) axon terminals and axon varicosities. D) cell bodies only. E) axon varicosities only.
C. axon terminals and axon varicosities.
66) Some neurotoxins work essentially the same way as some local anesthetics, which is to A) prevent depolarization by blocking Na+ entry into the cell only. B) inactivate the enzyme that activates the neurotransmitter and bind to Na+ channels. C) bind to Na+ channels and prevent depolarization by blocking Na+ entry into the cell. D) bind to Na+ channels only. E) inactivate the enzyme that activates the neurotransmitter only.
C. bind to Na+ channels and precent depolarization by blocking Na+ entry into the cell.
107) A home satellite dish receives signals from a satellite in outer space, allowing your television to display TV shows. Which part of a neuron is similar to the satellite dish? A) axon B) varicosities C) dendrites D) collaterals E) cell body
C. dendrites
60) The absolute refractory period of an action potential A) only prevents summation of action potentials. B) only ensures one-way travel down an axon. C) ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials. D) only allows a neuron to ignore a second signal sent that closely follows the first. E) ensures one-way travel down an axon and allows a neuron to ignore a second signal sent that closely follows the first.
C. ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.
17. How would the absolute refractory period be affected if voltage-gated sodium channels remained inactived? A. it would be the same whether the channels remained inactivated or not. B. It would be shorter than normal. C. It would be longer than normal D. None of these answers are correct.
C. it would be longer than normal
75) If a hyperpolarizing graded potential and a depolarizing graded potential of similar magnitudes arrive at the trigger zone at the same time, what is most likely to occur? A) The cell becomes easier to excite. B) The cell dies. C) Nothing. They will cancel each other out. D) The cell becomes hyperpolarized. E) An action potential is fired off more quickly than usual.
C. nothing. they will cancel each other out.
101) The point during an action potential when the inside of the cell has become more positive than the outside is known as the A) falling phase. B) peak. C) overshoot. D) depolarization. E) rising phase.
C. overshoot
70) When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs? A) hyperpolarization B) inhibition of the impulse C) temporal summation D) spatial summation E) decrease in speed of impulse transmission
C. temporal summation
95) Identify the FALSE statement. A) The voltage-gated sodium and potassium channels begin to open during the depolarization. B) Under normal conditions, all action potentials in a given cell are identical. C) The amplitude of the action potential depends on the amplitude of the graded potential that precedes it. D) Ions diffuse at nodes of Ranvier.
C. the amplitude of the action potential depends on the amplitude of the graded potential that precedes it.
22. If a stimulating electrode is placed in the middle of a resting axon and an above- threshold voltage is applied to the electrode, action potentials A) will not occur. B) will start at that point and travel only toward the axon terminal. C) will start at that point and travel in both directions in the axon. D) will start at that point and travel only toward the cell body.
C. will start at that point and travel in both directions in the axon.
92) The following are steps involved in transmission at the cholinergic synapse: 1. Chemically gated ion channels on the postsynaptic membrane are opened. 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) 2, 4, 1, 3, 5. B) 4, 2, 1, 5, 3. C) 3, 2, 4, 5, 1. D) 1, 2, 3, 4, 5. E) 2, 5, 4, 1, 3.
C.3,2,4,5,1
55) The term hyperkalemia specifically indicates too much potassium in which fluid compartment? A) intracellular B) interstitial C) plasma D) All of the answers are correct.
C.plasma
50) During the relative refractory period, an initial threshold-level depolarization is usually not sufficient to initiate an action potential. Why? A) Only a few K+ channels have returned to their resting position. B) Only some Na+ channels have returned to their resting position. C) The statement is incorrect; a threshold-level depolarization always triggers an action potential. D) Some Na+ channels have returned to their resting position and K+ channels are still open, so Na+ entry is offset by K+ loss. E) Only K+ channels are still open, so Na+ entry is offset by K+ loss.
D) Some Na+ channels have returned to their resting position and K+ channels are still open, so Na+ entry is offset by K+ loss.
57) In response to binding a neurotransmitter, a postsynaptic cell can A) only open chemically gated ion channels, causing graded potentials known as fast synaptic potentials. B) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell. C) only close ion channels through G proteins and second messenger systems, producing slow responses. D) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials, close ion channels through G proteins and second messenger systems, producing slow responses, and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell. E) only regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
D) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials, close ion channels through G proteins and second messenger systems, producing slow responses, and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
58) The basis of integration of neural information is A) the area under the curve of postsynaptic potentials overlapping in time and space. B) spontaneous activity in pacemaker neurons. C) command signals from central pattern generators. D) addition of postsynaptic potentials overlapping in time and space.
D. Addition of postsynaptic potentials overlapping in time and space.
40) If the sodium-potassium pumps in the cell membrane of a neuron fail to function, over time A) the intracellular concentration of sodium ion will increase. B) the membrane resting potential will become more positive than normal. C) the extracellular concentration of potassium ion will increase. D) All of the answers are correct.
D. All of the answers are correct.
24) In the membrane of a resting nerve cell, when chemically gated Cl- channels open, A) Cl- ions leave the cell and the cell becomes depolarized. B) Cl- ions leave the cell. C) Cl- ions enter the cell and the cell becomes depolarized. D) Cl- ions enter the cell. E) the cell becomes depolarized.
D. Cl- ions enter the cell
36) The primary problem in hyperkalemia is that A) neurons are easier to excite because their resting potential is closer to threshold. B) neurons are harder to excite because their resting potential is hyperpolarized and neurons respond too quickly to smaller graded potentials. C) neurons respond too quickly to smaller graded potentials. D) neurons are easier to excite because their resting potential is closer to threshold and neurons respond too quickly to smaller graded potentials. E) neurons are harder to excite because their resting potential is hyperpolarized.
D. Neurons are easier to excite because their resting potential is closer to threshold and neurons respond too quickly to smaller graded potentials.
91) Myelin is formed by A) axons only. B) oligodendrocytes only. C) Schwann cells only. D) Schwann cells and oligodendrocytes.
D. Schwann cells and oligodendrocytes.
94) Which statement is true when a neuron is at rest? A) The activation gate is closed. B) The inactivation gate is open. C) The activation gate is closed and no Na+ crosses the membrane. D) The activation gate is closed and the inactivation gate is open. E) No Na+ crosses the membrane.
D. The activation gate is closed and the inactivation gate is open.
64) Conduction speed can be increased by A) increasing the diameter of a neuron. C) removing myelin. B) increasing the length of a neuron. D) All of the above.
D. all of the above
54) Once the action potential reaches the axon terminal, what happens next? A) release of a neurotransmitter into the synaptic cleft B) release of a neurohormone into the blood C) exocytosis of a neurocrine D) Any of the above could happen next.
D. any of the above could happen next.
8) Once a stimulus binds a receptor on the cell's membrane, what could happen next? A) The membrane permeability is altered. B) Ion channels open, allowing ions to enter or exit. C) A second messenger is activated on the inside of the cell. D) Any of these actions could happen next.
D. any of these actions could happen next
46) The multiple thin, branched structures on some neurons whose main function is to receive incoming signals are the A) axons. B) cell bodies. C) soma. D) dendrites. E) None of the answers are correct.
D. dendrites
114) An excitatory postsynaptic potential (EPSP) A) hyperpolarizes a neuron, increasing the likelihood of an action potential. B) depolarizes a neuron, decreasing the likelihood of an action potential. C) hyperpolarizes a neuron, decreasing the likelihood of an action potential. D) depolarizes a neuron, increasing the likelihood of an action potential.
D. depolarizes a neuron, increasing the likelihood of an action potential .
88) The tip of an embryonic nerve cell's axon is called a A) stem tip. B) growth tip. C) kissing cone. D) growth cone. E) None of the answers are correct.
D. growth cone
88. Interneurons are found A) only in spinal nerves. B) only in the spinal cord. C) throughout the nervous system. D) in the CNS. E) only in the brain.
D. in the CNS
115) Learning and memory are thought to be due to synaptic changes known as A) modulation. B) excitation. C) inhibition. D) long-term potentiation. E) facilitation.
D. long-term potentiation
83) Caffeine, nicotine, and alcohol all have effects on A) action potential conduction. B) neurotransmitter reuptake. C) long-term potentiation. D) synaptic activity. E) neurotransmitter degradation.
D. synaptic activity.
117) The changing of activity at synapses, which occurs throughout life, is termed A) senility. B) elasticity. C) intelligence. D) synaptic plasticity. E) synchronicity.
D. synaptic plasticity.
52) The total amount of neurotransmitter released at the axon terminal is directly related to the A) amplitude of the graded potential. B) length of the axon. C) amplitude of the action potential. D) total number of action potentials.
D. total number of action potentials
74) The term axonal transport refers to A) the release of neurotransmitter molecules from the axon terminal. B) the movement of the axon terminal to synapse with a new postsynaptic cell. C) the transport of microtubules to the axon for structural support. D) vesicle transport of proteins and organelles down the axon. E) None of the answers are correct.
D. vesicle transport of proteins and organelles down the axon.
110) Information coming into the central nervous system is transmitted along ________ neurons. A) efferent B) sensory C) afferent D) afferent and sensory E) sensory and efferen
D.afferent and sensory
11) When comparing action potentials to graded potentials, an/two important distinguishing characteristic/s is/are A) action potentials can undergo summation. B) action potentials can undergo summation and the rate of action potentials is limited by the refractory period. C) graded potentials can undergo summation. D) graded potentials can undergo summation and the rate of action potentials is limited by the refractory period. E) that the rate of action potentials is limited by the refractory period.
D.graded potentials can undergo summation and the rate of action potentials is limited by the refractory period.
111) The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called A) prostheses. B) projections. C) protrusions. D) processes.
D.processes
108) Graded potentials can A) only act as signals over short distances. B) act as signals over long distances and make an action potential more or less likely. C) only make an action potential more or less likely. D) only act as signals over long distances. E) act as signals over short distances and make an action potential more or less likely.
E. Act as signals over short distances and make an action potential moe amor less likely.
20. Graded potentials may A) hyperpolarize the membrane. B) be called EPSPs or IPSPs. C) depolarize the membrane to the threshold voltage. D) initiate an action potential. E) All of the statements are true.
E. All of the statements are true.
93) 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 and two excitatory stimuli may be additive, and summation could occur. B) Two inhibitory stimuli may be additive, resulting in lower excitability. C) Two excitatory stimuli may be additive, and summation could occur. D) An excitatory and inhibitory signal can cancel each other out. E) An excitatory and inhibitory signal can cancel each other out; two excitatory stimuli may be additive, and summation could occur; and two inhibitory stimuli may be additive, resulting in lower excitability.
E. An excitatory and inhibitory signal can cancel each other out;two excitatory stimuli may be additive, and summation could occur; and two inhibitory stimuli may be additive, resulting in lower excitability.
18. Which of the following is a possible mechanism for presynaptic facilitation? A) extracellular concentration of sodium increases. B) calcium channels in the presynaptic membrane are inhibited. C) extracellular concentration of potassium increases. D) temporal summation occurs. E) calcium channels in the presynaptic membrane remain open longer.
E. Calcium Channels in the presynaptic membrane remain open longer.
31) What stops the rising phase of the action potential? A) The Na+ activation gate opens. B) The Na+ inactivation gate opens. C) The K+ gate closes. D) The sodium activation gate closes. E) The Na+ inactivation gate closes.
E. The Na+ inactivation gate closes
104) The Nernst equation can be used to predict A) the membrane potential resulting from all permeable ions. B) the threshold membrane potential. C) extracellular ion concentrations. D) intracellular ion concentrations. E) the membrane potential resulting from permeability to a single ion.
E. The membrane potential resulting from permeability to a single ion.
28) Which is NOT a known drug effect on synaptic function? A) decrease neurotransmitter binding to receptors B) decrease neurotransmitter synthesis C) change the rate of neurotransmitter release D) decrease neurotransmitter inactivation E) change the type of neurotransmitter found in the synaptic vesicle
E. change the type of neurotransmitter found in the synaptic vesicle
4) Voltage-gated channels are located A) in the membranes of axons only. B) on the neuron cell body only. C) within the cytosol only. D) in the membranes of dendrites only. E) in the membranes of dendrites, in the membranes of axons, and on the neuron cell body.
E. in the membranes of dendrites, in the membranes of axons, and on the neuron cell body.
44) Presynaptic facilitation makes a pathway A) less likely to be in use, just through hyperpolarization of selected neurons. B) less likely to be in use, just through hyperpolarization of selected neurons and capable of alteration, just through training and conditioning. C) more likely to be in use, just through depolarization of selected neurons. D) capable of alteration, just through training and conditioning. E) more likely to be in use, just through depolarization of selected neurons and capable of alteration, just through training and conditioning.
E. more likely to be in use, just through depolarization of selected neurons and capable of alteration, just through training and conditioning.
103) During childhood, growth and development of the brain PRIMARILY occurs by increasing A) neuron size only. B) neuron numbers and neuron size. C) number of dendrites and synapses only. D) neuron numbers only. E) neuron size and number of dendrites and synapses.
E. neuron size and number of dendrites and synapses.
10) The inhibitory neurotransmitters of the CNS act by opening ________ channels. A) only Ca2+ B) only K+ C) only Na+ D) Na+ and K+ E) only Cl-
E. only Cl-
34) The channelopathy known as Q-T syndrome is a result of mutation in ________ channels. A) chloride B) calcium C) sodium D) potassium E) sodium, potassium, or calcium
E. sodium, potassium, or calcium
7) Arrange the following events in the proper sequence: 1. Efferent neuron graded potential reaches threshold and fires an action potential. 2. Afferent neuron graded potential reaches threshold and fires an action potential. 3. Target organ responds. 4. CNS reaches decision about response. 5. Sensory receptor detects change in the environment.
E.5,2,4,1,3
51) These glial cells may contribute to Lou Gehrig's disease. A) Schwann cells B) ependymal cells C) astrocytes D) oligodendrocytes E) microglia
E.Microglia
3) Glial cells A) provide structural and metabolic support and help maintain homeostasis of the brain's extracellular fluid. B) only provide structural and metabolic support. C) only help maintain homeostasis of the brain's extracellular fluid. D) only guide neurons during growth and repair. E) All of the answers are correct.
E.all of the answers are correct
59) The brain and spinal cord together compose the A) autonomic division. B) peripheral nervous system. C) somatic motor division. D) visceral nervous system. E) central nervous system
E.central nervous system
119) Graded potentials that arrive at postsynaptic neurons are called ________ if they make that cell more likely to fire an action potential.
Excitatory
120) In spatial summation the same presynaptic neuron is repeated until a threshold level of depolarization is reached.
False, temporal
145) The time during which an excitable membrane cannot respond to further stimulation regardless of the stimulus strength is the ________.
absolute refractory period
128) The ________ phenomena states that the properties of the action potential are independent of the relative strength of the depolarizing stimulus.
all-or-none
141) Products from the cell body of a neuron are transported to the axon terminals by ________.
anterograde transport
155) highly branched cells that provide neurons with metabolic substrates
astrocytes
160) may be covered with myelin
axon
156) make proteins necessary for repair of damaged neuron
cell bodies
159) astrocytes
central nervous system
137) At a(n) ________ synapse, a neurotransmitter is released to affect the postsynaptic cell.
chemical
129) The sum of all of the electrical and chemical gradients active across the membrane is known as the ________.
driving force
126) In a(n) ________ synapse, there is a direct physical connection between cells.
electrical
175) cells that create a selectively permeable epithelial layer to separate fluid compartments of the CNS
ependymal cells
125) The gaps between Schwann cells are called synapses.
false, nodes of ranvier
140) Schwann cells are the glial cell associated with myelination the central nervous system.
false, peripheral nervous system
147) can involve chemically gated ion channels
graded potential
157) may be hyperpolarizing
graded potential
158) size increases if stimulus strength increases
graded potential
133) The two types of electrical signals in neurons are ________.
graded potentials action potentials
124) Graded potentials that arrive at postsynaptic neurons are called ________ if they make that cell less likely to fire an action potential.
inhibitory
143) Graded potentials that increase the likelihood of an action potential bring the ________ closer to threshold.
membrane potential
136) Receptors that work through second messenger systems are called ________ receptors.
metabotropic
154) specialized immune cells in the CNS
microglia
138) The gaps between adjacent Schwann cells on an axon are called ________.
nodes of ranvier
152) cells that myelinate several axons
oligo
130) The period of time during which an excitable membrane can respond again, but only if the stimulus is greater than the initial stimulus is the ________.
relative refractory period
167) cells that form supportive capsule around cell bodies
satellite cells
150) cells that myelinate only one axon each; multiple glial cells per axon
schwann cells
131) The addition of several stimuli arriving from different locations on the same cell to produce an action potential is called ________.
spatial summation
135) For ________ to occur, a second potential must arrive before a previous one has been completed.
summation
142) When two or more graded potentials arrive at the trigger zone within a short period of time, their effects are additive and ________ occurs.
temporal summation
144) The addition of stimuli arriving one after another to produce an action potential is called ________.
temporal summation
121) The minimum amount of stimulus required to depolarize an excitable membrane and generate an action potential is known as the ________.
threshold