NERVOUS SYS QUESTIONS

97. The same neurotransmitter may produce different effects on neurons because of differences in the A. type of receptors on the postsynaptic membranes of neurons. B. strength of the action potential. C. amount of neurotransmitter. D. size of the neurons. E. potassium channels.

A. type of receptors on the postsynaptic membranes of neurons.

44. Gray matter on the surface of the brain is/are called A. the cortex. B. nuclei. C. ganglia. D. tracts.

A. the cortex.

82. Chemical synapses are characterized by A. the release of neurotransmitter by the presynaptic terminal. B. connexons that connect the pre- and postsynaptic cells. C. the presence of receptors for neurotransmitters on the presynaptic terminal. D. the absence of gap junctions. E. receptors located only on the presynaptic terminal.

A. the release of neurotransmitter by the presynaptic terminal.

19. Axons contain A. the trigger zone. B. foot processes. C. Nissl bodies. D. the soma. E. the rough endoplasmic reticulum.

A. the trigger zone.

13. The junction of a neuron with another cell is a/an A. synapse. B. ganglion. C. receptor. D. effector.

A. synapse.

54. In hyperpolarization A. K+ ions tend to diffuse out of the cell. B. the plasma membrane's permeability to K+ decreases. C. the resting membrane potential moves closer to zero. D. Na+ ions enter the cell in large numbers. E. the resting membrane potential becomes more positive.

A. K+ ions tend to diffuse out of the cell.

88. Why isn't an action potential transmitted from a postsynaptic membrane to a presynaptic terminal? A. Presynaptic terminals have no acetylcholine receptors. B. Presynaptic neurons do not have a resting membrane potential. C. Acetylcholine can only diffuse in one direction across the synaptic cleft. D. Synaptic vesicles in the postsynaptic membrane are inactive. E. Acetylcholine is destroyed too fast.

A. Presynaptic terminals have no acetylcholine receptors.

34. Which of the following is true? A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes.. B. Myelination will not influence the speed of conduction of action potentials. C. The myelin sheath inhibits the flow of electrical charges at nodes. D. The myelin sheath is a protein wrapping. E. The myelin sheath does not electrically insulate the axons from one another.

A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes..

64. A stimulus either causes an action potential or it doesn't. This is called A. an all-or-none response. B. a graded response. C. a latent period response. D. a relative refractory response. E. a local response.

A. an all-or-none response.

17. Dendrites A. are the input part of the neuron. B. conduct action potentials away from the cell body. C. are generally long and unbranched. D. form synapses with the microglia. E. contain the trigger zone.

A. are the input part of the neuron.

28. A neuroglial cell that is a major component of the blood-brain barrier is the A. astrocyte. B. microglial cell. C. oligodendrocyte. D. ependymal cell. E. macrophage.

A. astrocyte.

2. Which of the following is responsible for problem-solving skills? A. central nervous system B. peripheral nervous system C. somatic nervous system D. autonomic nervous system E. None of these choices is correct.

A. central nervous system

40. Action potentials are conducted more rapidly when transmission is A. from node to node on a myelinated axon. B. on a small diameter axon. C. on an unmyelinated axon. D. from internode to internode. E. from internode to node on a myelinated axon.

A. from node to node on a myelinated axon.

6. Cell bodies of the peripheral nervous system are located in A. ganglia. B. Schwann cells. C. the motor division. D. the sensory division. E. nerves.

A. ganglia

102. What inhibitory neurotransmitter is blocked in strychnine poisoning? A. glycine B. acetylcholine C. glutamate D. adenosine

A. glycine

74. The absolute refractory period ends when A. inactivation gates of voltage-gated Na+ ion channels reopen. B. activation gates of voltage-gates Na+ ion channels reopen. C. the sodium-potassium exchange pump stops. D. voltage-gated K+ channels open. E. None of these choices is correct.

A. inactivation gates of voltage-gated Na+ ion channels reopen.

11. The central nervous system A. is the site for processing information. B. initiates visual and auditory stimuli. C. consists of 43 pairs of nerves. D. is totally involuntary. E. does not interact with the peripheral nervous system.

A. is the site for processing information.

59. A change in resting membrane potential confined to a small area is called a(n) A. local potential. B. action potential. C. summated potential. D. after potential. E. resting membrane potential.

A. local potential.

91. Rapid removal or destruction of neurotransmitter in the synaptic cleft A. may affect the ability of the postsynaptic membrane to generate action potentials. B. generates local potentials in the presynaptic terminal. C. is necessary for synaptic transmission. D. may lead to action potentials. E. may stop exocytosis.

A. may affect the ability of the postsynaptic membrane to generate action potentials.

33. Which of the following is mismatched? A. microglia - provide support for the neuron cell body B. astrocytes - blood-brain barrier C. oligodendrocytes - form myelin sheaths D. ependymal cells - produce cerebrospinal fluid E. ependymal cells - choroid plexus

A. microglia - provide support for the neuron cell body

62. An action potential A. occurs when the local potential reaches threshold level. B. propagates across the plasma membrane in a decremental fashion. C. has no repolarization phase. D. is an example of negative feedback. E. cannot transmit information.

A. occurs when the local potential reaches threshold level.

69. During depolarization of the plasma membrane, A. sodium ions move rapidly into the cell. B. potassium ions move rapidly out of the cell. C. membrane permeability to sodium ions decreases. D. the outside of the cell becomes positively charged relative to the inside. E. sodium ions move rapidly out of the cell.

A. sodium ions move rapidly into the cell.

63. Which of the following events is NOT a characteristic of an action potential? A. The plasma membrane becomes highly permeable to sodium ions and depolarization results. B. As sodium ions enter, the inside of the plasma membrane becomes more negative. C. At the peak of depolarization, sodium channels begin to close and potassium channels open. D. In repolarization, potassium ions flow out of the cell. E. Action potentials occur according to the all-or-none principle.

B. As sodium ions enter, the inside of the plasma membrane becomes more negative.

101. What is the only neurotransmitter released at the neuromuscular junction? A. serotonin B. acetylcholine C. dopamine D. glutamate

B. acetylcholine

30. Microglia A. are part of the blood-brain barrier. B. are phagocytic cells in the CNS. C. produce cerebrospinal fluid. D. form myelin sheaths. E. are part of the choroid plexus.

B. are phagocytic cells in the CNS.

24. Neurons that have a single axon and a single dendrite are A. tripolar. B. bipolar. C. multipolar. D. pseudo-unipolar.

B. bipolar.

98. The function of acetylcholinesterase is to A. open voltage-gated sodium gates. B. breakdown acetylcholine in the synapse. C. produce an IPSP on the postsynaptic membrane. D. metabolize norepinephrine.

B. breakdown acetylcholine in the synapse.

41. White matter is composed of A. ganglial sheaths. B. bundles of myelinated axons. C. collections of nerve cell bodies. D. bundles containing both myelinated axons and nerve cell bodies. E. collections of unmyelinated axons.

B. bundles of myelinated axons.

73. The absolute refractory period assures A. prolonged depolarization during the action potential. B. completion of repolarization before another action potential. C. that no after-potential occurs. D. reversal of the direction of propagation of the action potential. E. that the stimulus is strong enough to elicit a response.

B. completion of repolarization before another action potential.

7. The sensory (afferent) division of the peripheral nervous system A. transmits action potentials to sensory organs. B. conveys action potentials to the CNS. C. stimulates glands to release hormones. D. stimulates muscle contractions. E. does not involve sensory receptors.

B. conveys action potentials to the CNS.

83. Gap junctions are functional __________ synapses. A. chemical B. electrical C. potential D. intracellular E. neuromuscular

B. electrical

9. The autonomic nervous system A. stimulates skeletal muscle contractions. B. has two sets of neurons in a series. C. is involved in problem solving. D. is under voluntary control. E. does not include the central nervous system.

B. has two sets of neurons in a series.

67. The opening of more and more Na+ ion channels during depolarization A. is the result of the sodium-potassium exchange pump. B. is an example of a positive feedback cycle. C. is possible only if K+ channels remain closed. D. is the cause of the afterpotential. E. is an example of a negative feedback cycle.

B. is an example of a positive feedback cycle.

72. During the absolute refractory period, the cell A. generates many local potentials. B. is insensitive to further stimulation. C. responds to even weak stimuli. D. reverses the direction of the action potential. E. is very sensitive.

B. is insensitive to further stimulation.

25. Neurons in the skin that are responsible for detecting pain are A. apolar. B. pseudo-unipolar. C. bipolar. D. multipolar.

B. pseudo-unipolar.

38. Which of the following is NOT a neuroglia of the CNS? A. ependymal cells B. satellite cells C. oligodendrocytes D. astrocytes

B. satellite cells

22. A neuron that conducts pain sensations to the central nervous system would be classified as a(n) A. motor neuron. B. sensory or afferent neuron. C. efferent neuron. D. association neuron. E. interneuron.

B. sensory or afferent neuron.

3. The central nervous system includes the A. ganglia. B. spinal cord. C. spinal nerves. D. cranial nerves. E. sensory receptors.

B. spinal cord.

85. The junction between two neurons is a A. ganglia. B. synapse. C. fascicle. D. node of Ranvier. E. neuromuscular junction.

B. synapse.

55. If the charge difference across the plasma membrane is decreased, A. the potential difference across the plasma membrane does not change. B. the membrane potential is more positive. C. the change is called hyperpolarization. D. negative proteins can leave the cell. E. the membrane potential is more negative.

B. the membrane potential is more positive.

47. The plasma membrane of a neuron is more permeable to potassium ions because A. of its positive electrical charge. B. there are more non-gated channels for K+ than Na+. C. protein molecules cannot exit through the cell membrane. D. calcium ions block Na+ and Cl- channels. E. there are more non-gated channels for Na+ than K+.

B. there are more non-gated channels for K+ than Na+.

65. In some cells, an afterpotential occurs because A. the sodium ions continue to enter the cell after depolarization is finished. B. there is prolonged, elevated permeability to potassium during repolarization. C. the sodium-potassium pump is actively exchanging ions across the membrane. D. the extracellular Na+ ion concentration is reduced. E. the permeability to sodium continues longer than necessary.

B. there is prolonged, elevated permeability to potassium during repolarization.

5. There are _____ pairs of cranial nerves and _____ pairs of spinal nerves. A. 10; 30 B. 31; 12 C. 12; 31 D. 30; 10 E. 12; 32

C. 12; 31

90. Neurotransmitter is being released at a synapse. Which of the following occurs last? A. Calcium ions enter the presynaptic terminal. B. Synaptic vesicles release neurotransmitter by exocytosis. C. An action potential is produced in the postsynaptic membrane. D. Neurotransmitter flows rapidly across the synaptic cleft. E. Neurotransmitter binds with the receptor on the postsynaptic membrane.

C. An action potential is produced in the postsynaptic membrane.

70. Each voltage-gated Na+ ion channel has two voltage sensitive gates: an activation gate and an inactivation gate. Which of the following would occur during depolarization? A. Activation gates are open; inactivation gates are closed. B. Activation gates are closed; inactivation gates are open. C. Both activation and inactivation gates are open. D. Both activation and inactivation gates are closed. E. None of these events occurs during depolarization.

C. Both activation and inactivation gates are open.

56. Which of the following situations occurs in electrically excitable cells? A. When Na+ ion channels open, K+ ion channels close. B. The sodium-potassium exchange pump moves sodium into the cell. C. Depolarization causes voltage-gated sodium ion channels to open. D. Ligand-gated sodium ion channels are opened by high extracellular calcium levels. E. Proteins tend to diffuse out of the cell.

C. Depolarization causes voltage-gated sodium ion channels to open.

26. Which of the following statements regarding neuroglia is false? A. Neuroglia serve as the major supporting tissue in the CNS. B. Neuroglia form part of the blood-brain barrier. C. Neuroglia produce action potentials for skeletal muscles. D. Neuroglia form myelin sheaths around some axons. E. Neuroglia produce cerebrospinal fluid.

C. Neuroglia produce action potentials for skeletal muscles.

48. Which of the following is true? A. The resting plasma membrane is more permeable to Na+ than K+. B. The resting membrane potential never reaches an equilibrium point. C. The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell. D. Negatively charged Cl- ions are attracted by negative charges in the cell. E. The purpose of the sodium-potassium exchange pump is to create an equilibrium of ion concentrations.

C. The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell.

96. When a neurotransmitter binds to its receptor and increases the permeability of the postsynaptic membrane to sodium ions, A. the membrane will be hyperpolarized. B. more chloride ions will also diffuse into the cell. C. an excitatory postsynaptic potential (EPSP) will result. D. the membrane will become impermeable to potassium ions. E. the sodium ions diffuse out of the cell.

C. an excitatory postsynaptic potential (EPSP) will result.

37. Which of the following is NOT true of reactive astrocytosis? A. injury site is blocked off B. scars limit regeneration C. causes the spread of inflammation D. reduces injury to surrounding tissue

C. causes the spread of inflammation

15. Protein synthesis in neurons occurs in A. axons. B. dendrites. C. cell bodies or soma. D. terminal boutons. E. node of Ranvier.

C. cell bodies or soma.

4. The peripheral nervous system includes the A. brain. B. spinal cord. C. cranial nerves. D. blood-brain barrier. E. cerebellum.

C. cranial nerves.

14. The enteric nervous system consists of plexuses within the walls of the A. brain. B. spinal cord. C. digestive tract. D. urinary bladder.

C. digestive tract.

92. Monamine oxidase inhibitors (MAO inhibitors) A. prevent synaptic transmission. B. enhance the breakdown of norepinephrine. C. enhance the binding of norepinephrine to its receptors. D. prevent the release of norepinephrine by the presynaptic terminal. E. have no effect on the action of norepinephrine.

C. enhance the binding of norepinephrine to its receptors.

76. As the strength of a stimulus is increased, the A. amplitude of the action potential increases. B. duration of the action potential increases. C. frequency of occurrence of action potentials increases. D. resonance of action potentials increases. E. height of the action potentials increases.

C. frequency of occurrence of action potentials increases.

93. Receptor molecules in synapses A. tend to concentrate on presynaptic terminals. B. bind irreversibly with neurotransmitter. C. have a high degree of specificity. D. serve as channel proteins. E. can bind to any molecule in the synapse.

C. have a high degree of specificity.

81. Local hyperpolarization in a synapse is called a(an) A. excitatory postsynaptic potential. B. resting membrane potential. C. inhibitory postsynaptic potential. D. gap junction potential. E. action potential.

C. inhibitory postsynaptic potential.

23. The motor neurons responsible for making a fist are A. tripolar. B. bipolar. C. multipolar. D. pseudo-unipolar. E. None of these choices are correct.

C. multipolar.

42. If you cut bundles of axons and their myelin sheaths in the PNS, you cut A. ganglia. B. nuclei. C. nerves. D. gray matter. E. nerve tracts.

C. nerves.

31. Multiple sclerosis is a neurological disorder in which myelin sheaths in the CNS are destroyed. Which of the following neuroglial cells is being damaged in multiple sclerosis? A. astrocyte B. microglial cell C. oligodendrocyte D. ependymal cell E. Schwann cells

C. oligodendrocyte

78. Continuous conduction of an action potential means that A. once one action potential is created, it moves down the axon. B. the whole axon depolarizes at the same time. C. one action potential stimulates the production of a new action potential at the adjacent site. D. an action potential is conducted from one node of Ranvier to the next node.

C. one action potential stimulates the production of a new action potential at the adjacent site.

10. Digestion of food is regulated by the A. sensory division. B. sympathetic division of the ANS. C. parasympathetic division of the ANS. D. somatic nervous system. E. None of these choices are correct.

C. parasympathetic division of the ANS.

86. Neurotransmitters are released from the A. epineurium. B. synaptic cleft. C. presynaptic terminal. D. postsynaptic membrane. E. calcium channels.

C. presynaptic terminal.

75. A stimulus that results in a local potential that does not reach threshold is called a A. threshold stimulus. B. maximal stimulus. C. subthreshold stimulus. D. supramaximal stimulus. E. local stimulus.

C. subthreshold stimulus.

8. The motor (efferent) division of the peripheral nervous system A. is a division of the CNS. B. regulates the digestion of food. C. transmits impulses from the CNS to skeletal muscle. D. has nerve cell bodies located in ganglia near the spinal cord and brain. E. detects a stimulus.

C. transmits impulses from the CNS to skeletal muscle.

80. The speed of an action potential depends upon A. whether an axon is myelinated or not myelinated. B. thickness of the myelin sheath. C. the diameter of the axon. D. All of the choices are correct.

D. All of the choices are correct.

32. Schwann cells differ from oligodendrocytes in which of the following ways? A. Schwann cells form myelin; oligodendrocytes do not. B. Oligodendrocytes are only found in the PNS; Schwann cells are only found in the CNS. C. Schwann cells form sheaths around several axons, while oligodendrocytes form sheaths around only one axon. D. Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons. E. None of these choices are true differences.

D. Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons.

36. Which of the following is NOT true about astrocytes? A. They can wall off an injury site to prevent spread of inflammation. B. They can prevent toxic substances from entering brain tissue. C. They can release chemicals that promote formation of synapses. D. They can aid in the regeneration of injured neurons.

D. They can aid in the regeneration of injured neurons.

71. If the ECF around a nerve cell is replaced with an isotonic saline solution that contains potassium ions and other solutes at concentrations very close to the ECF concentrations of a normal cell, the result is A. no resting membrane potential. B. hyperpolarized membrane. C. depolarized membrane. D. a resting membrane potential close to its normal value. E. None of these choices is correct.

D. a resting membrane potential close to its normal value.

79. Saltatory conduction of an action potential means that A. once one action potential is created, it moves down the axon. B. the whole axon depolarizes at the same time. C. one action potential stimulates the production of a new action potential at the adjacent site. D. an action potential is conducted from one node of Ranvier to the next node.

D. an action potential is conducted from one node of Ranvier to the next node

16. Nissl bodies are A. part of a dendrite. B. also called gemmules. C. lipid droplets. D. areas of rough endoplasmic reticulum. E. part of the Golgi apparatus.

D. areas of rough endoplasmic reticulum.

77. The strength of a stimulus is communicated through A. changes in the magnitude of the action potential. B. the frequency of the action potentials. C. the length of time action potentials are produced. D. both the frequency and the length of time action potentials are produced.

D. both the frequency and the length of time action potentials are produced.

100. What ion is necessary for the release of neurotransmitter from synaptic vesicles? A. chloride B. sodium C. potassium D. calcium

D. calcium

89. Neurotransmitters A. stimulate presynaptic terminals. B. remain in the synaptic cleft for long periods of time. C. bind irreversibly to the receptor molecules of the postsynaptic membrane. D. cause the production of action potentials in the postsynaptic membrane. E. do not affect membrane channels in the postsynaptic membrane.

D. cause the production of action potentials in the postsynaptic membrane.

94. Receptor molecules A. are nonspecific. B. are always lipids. C. attach to the synaptic cleft. D. determine whether a neurotransmitter will be excitatory or inhibitory. E. are not attached to ligand-gated channels.

D. determine whether a neurotransmitter will be excitatory or inhibitory.

18. Axons A. contain the nucleus. B. are numerous extensions from each neuron. C. do not have a trigger zone. D. have a distal portion that branches to form the presynaptic terminals. E. do not have a resting membrane potential.

D. have a distal portion that branches to form the presynaptic terminals.

49. Mr. Miller has been hospitalized for the flu. The flu virus increases membrane permeability to potassium. You would expect his cells to A. depolarize. B. repolarize. C. isopolarize. D. hyperpolarize. E. hypopolarize.

D. hyperpolarize.

58. A local potential A. does not occur until threshold. B. transmits information from one cell to another. C. might be a depolarization event but cannot be a hyperpolarization event. D. increases or decreases in direct proportion to the stimulus strength. E. does not alter resting membrane potential.

D. increases or decreases in direct proportion to the stimulus strength.

87. Damage to a postsynaptic membrane would A. increase neurotransmitter release. B. decrease the release of neurotransmitter. C. increase neurotransmitter production. D. interfere with the ability to respond to neurotransmitter. E. destroy vesicles containing neurotransmitter.

D. interfere with the ability to respond to neurotransmitter.

50. For the resting membrane potential, increasing the sodium ion concentration in the ECF results in A. hyperpolarization. B. depolarization. C. hypopolarization. D. little change in membrane potential. E. There is not enough information to determine the results.

D. little change in membrane potential

35. Gaps or interruptions in the myelin sheath are called A. internodes. B. tight junctions. C. neurofilaments. D. nodes of Ranvier. E. gap junctions.

D. nodes of Ranvier.

43. Clusters of gray matter deep within the brain are called A. cortices. B. nerves. C. ganglia. D. nuclei.

D. nuclei.

66. When repolarization of a neuron is complete, the A. neuron dies. B. neuron regenerates. C. cell no longer has a potential difference across its membrane. D. original polarity of the neuron is restored. E. neuron is no longer excitable.

D. original polarity of the neuron is restored.

20. Synaptic vesicles contain neurotransmitters and are present in the A. dendrites. B. cell body. C. axolemma. D. presynaptic terminals. E. trigger zone.

D. presynaptic terminals.

27. The blood-brain barrier A. permits passage of foreign substances from the blood to the neurons. B. prohibits the transport of amino acids and glucose to the neurons. C. prohibits the removal of waste materials from the neurons. D. protects neurons from toxic substances in the blood. E. does not prevent fluctuations in the composition of the blood from affecting the functions of the brain.

D. protects neurons from toxic substances in the blood.

39. What type of neuroglial cells provide support and nutrition to sensory ganglia in the PNS? A. Schwann cells B. microglia C. ependymal cells D. satellite cells

D. satellite cells

61. Depolarization of the nerve cell membrane occurs when there is a rapid influx (inflow) of A. potassium ions. B. chloride ions. C. calcium ions. D. sodium ions. E. proteins.

D. sodium ions.

12. Which of the following is mismatched? A. central nervous system - brain B. autonomic nervous system - sympathetic and parasympathetic divisions C. peripheral nervous system - spinal nerves D. somatic nervous system - sensory division of PNS E. peripheral nervous system - sensory and motor divisions

D. somatic nervous system - sensory division of PNS

99. Action potentials at a chemical synapse A. travel from presynaptic terminal to postsynaptic membrane. B. travel from postsynaptic membrane to presynaptic terminal. C. travel back and forth from presynaptic terminal to postsynaptic membrane. D. travel from presynaptic terminal to presynaptic membrane. E. stop at the presynaptic terminal and are regenerated on the postsynaptic membrane.

D. travel from presynaptic terminal to presynaptic membrane.

84. Arrange the events of synaptic transmission in correct sequence. (1) sodium ions diffuse into the cell and cause a local potential (2) neurotransmitter binds with receptor on postsynaptic cell (3) neurotransmitter diffuses across the synaptic cleft (4) membrane permeability to sodium ions on postsynaptic cell increases (5) action potential causes release of neurotransmitter A. 5, 2, 3, 4, 1 B. 5, 2, 3, 1, 4 C. 5, 3, 4, 1, 2 D. 5, 4, 3, 2, 1 E. 5, 3, 2, 4, 1

E. 5, 3, 2, 4, 1

1. The nervous system A. monitors internal and external stimuli. B. transmits information in the form of action potentials. C. interprets or assesses information. D. maintains homeostasis. E. All of these choices are correct.

E. All of these choices are correct.

68. Which of the following statements regarding voltage-gated K+ channels is true? A. These channels have only one gate. B. These channels open more slowly than Na+ channels. C. Once open, these channels remain open until repolarization is complete. D. These channels are specific for potassium. E. All of these statements are true.

E. All of these statements are true.

52. Which of the following statements accurately describe events that occur as a result of a local potential reaching threshold? A. Activation gates of Na+ ion channels begin to close. B. Inactivation gates of Na+ ion channels begin to open. C. A positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open. D. K+ ion channels begin to close. E. Inactivation gates of Na+ ion channels begin to open and a positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open.

E. Inactivation gates of Na+ ion channels begin to open and a positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open.

53. Which of the following events will lead to depolarization? A. an increase in K+ ions in the extracellular fluid B. a decrease in K+ ions in the extracellular fluid C. an increase in the rate of diffusion of K+ ions from cells D. an increase in Na+ ions in the extracellular fluid E. None of these events would cause depolarization.

E. None of these events would cause depolarization.

60. Which of the following situations will lead to hyperpolarization? A. increase the permeability of the plasma membrane to Na+ ions B. decrease the permeability of the plasma membrane to K+ ions C. decrease the permeability of the plasma membrane to chloride ions D. any positive ion entering the cell E. None of these situations will lead to hyperpolarization.

E. None of these situations will lead to hyperpolarization.

51. A change in the resting membrane potential has the following characteristics (non-propagated, graded, can summate). This type of change can A. be a local potential. B. be an action potential. C. be a consequence of an increase in the permeability to Na+. D. result in repolarization. E. be a local potential and a consequence of an increase in the permeability to Na+.

E. be a local potential and a consequence of an increase in the permeability to Na+.

57. Voltage-gated sodium channels are sensitive to changes in the extracellular concentration of A. potassium ions. B. proteins. C. sodium ions. D. chloride ions. E. calcium ions.

E. calcium ions.

29. Overproduction of cerebrospinal fluid could be the result of overactivity of the A. astrocytes. B. microglial cells. C. oligodendrocytes. D. macrophages. E. ependymal cells.

E. ependymal cells.

21. A neuron that carries action potentials from one neuron to another is called a(n)____________. A. motor neuron B. sensory neuron C. afferent neuron D. efferent neuron E. interneuron

E. interneuron

95. A neuromodulator A. acts as a neurotransmitter. B. inactivates neurotransmitters. C. is a receptor site for a neurotransmitter. D. has no influence on the amount of neurotransmitter released. E. is a substance released from neurons that influences the sensitivity of neurons to neurotransmitters.

E. is a substance released from neurons that influences the sensitivity of neurons to neurotransmitters.