Nervous System Nervous Tissue Full Test Bank Chapter 12

Anatomy & Physiology, 3e (McKinley)

Chapter 12 Nervous System: Nervous Tissue

1) Receptors are parts of the nervous system that allow it to

A) initiate responses to information.

B) process information.

C) collect information.

D) conduct impulses to muscles.

2) The nervous system controls the activity of muscles and glands. Muscles and glands can generate changes and are therefore called

A) afferents.

B) effectors.

C) stimuli.

D) visceral.

3) Nerves and ganglia are structures found in the

A) central nervous system.

B) peripheral nervous system.

C) central and peripheral nervous systems.

4) Which is not a general function of the nervous system?

A) Transporting materials throughout the body

B) Collecting information

C) Processing and evaluating information

D) Responding to information

E) No exceptions; all are general functions of the nervous system.

5) The spinal cord is part of the central nervous system.

6) The afferent division of the nervous system is also known as the ________ division.

A) motor

B) cranial

C) ganglial

D) efferent

E) sensory

7) Which is not a function of the motor division of the nervous system?

A) Conducts impulses from the CNS

B) Transmits impulses to muscles and glands

C) Transmits impulses from the viscera

D) Voluntary control of skeletal muscle

E) Involuntary control of the heart

8) The portion of the nervous system that conducts impulses from the skin, joints, skeletal muscles, and special senses is the ________ division.

A) autonomic motor

B) somatic sensory

C) somatic motor

D) visceral sensory

9) The portion of the nervous system that has voluntary control over skeletal muscles is the ________ division.

A) autonomic motor

B) somatic sensory

C) somatic motor

D) visceral sensory

10) A neuron conducting an impulse from the CNS to the detrusor muscle of the urinary bladder would be classified as a(n) ________ neuron.

A) autonomic motor

B) somatic sensory

C) somatic motor

D) visceral sensory

11) A neuron conducting an impulse from the stomach wall to the CNS would be classified as a(n) ________ neuron.

A) autonomic motor

B) somatic sensory

C) somatic motor

D) visceral sensory

12) The motor nervous system is also known as the ________ nervous system.

13) Which is not characteristic of neurons?

A) High mitotic rate

B) High metabolic rate

C) Require continuous supplies of glucose and oxygen

D) Extreme longevity

E) No exceptions; all of these are characteristic of neurons.

14) Conductive activity in a neuron generally causes it to secrete

A) a specific neurotransmitter that either excites or inhibits its target.

B) a specific neurotransmitter that always excites its target.

C) several types of neurotransmitters simultaneously, all of which excite the cell's target.

D) several types of neurotransmitters simultaneously, that are broadcast to excite and inhibit multiple targets.

E) several types of neurotransmitters simultaneously, that all work to prevent another immediate impulse.

15) Which statement is consistent with the current understanding of neural tissue?

A) A person is born with all of the neurons they will ever have.

B) Most neurons formed in fetal development last a lifetime, but some brain regions in adults can generate new neurons.

C) Neurons are constantly dying and being replaced throughout all regions of the brain.

D) Stem cells in the brain become glia, which can later become neurons if there is a need for them to do so.

16) Which part of the neuron contains the nucleus?

A) Dendrite

B) Axon

C) Soma

D) Axon hillock

E) Synaptic knob

17) Where are synaptic knobs located?

A) At the distal ends of an axons

B) At the ends of dendrites

C) Within the cell body

D) Along axon collaterals

E) At the axon hillock

18) The cytoplasm within a cell body of a neuron is called the

A) soma.

B) perikaryon.

C) neurokaryon.

D) chromatophilic substance.

E) chromatophobic substance.

19) What structures extend into the axon and dendrite of a neuron to provide tensile strength?

A) Motor filaments

B) Nissl bodies

C) Telodendria

D) Neurofibrils

E) Collateral fibers

20) Electrical signals are conducted toward the cell body of a neuron by its ________.

21) Anterograde transport is the movement of materials from synaptic knobs to the cell body.

22) Fast axonal transport is

A) passive and only occurs in the anterograde direction.

B) passive and only occurs in the retrograde direction.

C) active (requires ATP) and only occurs in the anterograde direction.

D) active (requires ATP) and only occurs in the retrograde direction.

E) active (requires ATP) and can occur in either the anterograde or retrograde direction.

23) Vesicles and glycoproteins required at the synapse are moved down a nerve fiber by ________ axonal transport.

A) fast

B) slow

24) Based on structure, the most common type of neuron is the ________ neuron.

A) multipolar

B) bipolar

C) unipolar

D) pseudounipolar

25) Based on function, the vast majority of neurons are

A) sensory neurons.

B) motor neurons.

C) unipolar neurons.

D) bipolar neurons.

E) interneurons.

26) The neurons that are responsible for integrating information by retrieving, processing, storing, and "deciding" how the body responds to stimuli are

A) sensory neurons.

B) motor neurons.

C) accessory neurons.

D) correlation neurons.

E) interneurons.

27) Which functional class of neurons lies entirely within the central nervous system?

A) Bipolar neurons

B) Sensory neurons

C) Interneurons

D) Unipolar neurons

E) Motor neurons

28) A bipolar neuron has

A) two axons extending from the cell body.

B) two dendrites extending from the cell body.

C) one axon and one dendrite extending from the cell body.

D) a single short process that extends from the cell body and then splits into a peripheral and a central branch.

29) Typically, a multipolar neuron has many dendrites and one axon extending from the cell body.

30) A nerve cell that has dendrites but no axons is categorized as a(n) ________ neuron.

31) A mixed nerve is one that contains both

A) cranial and spinal nerve fibers.

B) sensory and motor neurons.

C) unipolar and bipolar neurons.

D) an endoneurium and an epineurium.

E) presynaptic and postsynaptic neurons.

32) Spinal nerves extend from the spinal cord, whereas ________ nerves extend from the brain.

33) In a mixed nerve,

A) some axons transmit sensory information and others transmit motor information.

B) individual axons transmit both sensory and motor information.

C) chemical synapses occur along with electrical synapses.

D) astrocytes are interspersed with ependymal cells.

34) Most commonly, a synapse is made between a

A) presynaptic neuron's dendrite and a postsynaptic membrane's cell body.

B) presynaptic neuron's axon and a postsynaptic neuron's dendrite.

C) presynaptic neuron's axon hillock and a postsynaptic neuron's cell body.

D) presynaptic neuron's soma and a postsynaptic neuron's synaptic knob.

35) When transmission occurs at a synapse, neurotransmitter is released by

A) the presynaptic neuron's synaptic knob into the synaptic cleft.

B) the postsynaptic neuron's dendrites into the synaptic cleft.

C) the presynaptic neuron's dendrites into the synaptic cleft.

D) the presynaptic neuron's soma into synaptic vesicles.

E) the postsynaptic neuron's telodendria into the axon hillock.

36) Electrical synapses involve coupling of neurons by

A) synaptic clefts.

B) desmosomes.

C) gap junctions.

D) satellite cells.

37) Which statement accurately compares the transmission speed of the different types of synapses?

A) Transmission at chemical synapses involves a brief synaptic delay, but electrical synapses are faster.

B) Transmission at both chemical and electrical synapses involves a synaptic delay of approximately 1 millisecond.

C) Transmission at electrical synapses involves a brief synaptic delay, but chemical synapses are faster.

D) Electrical synapses have a constant delay of 1 millisecond, but chemical synaptic delays vary between 0.1 and 0.3 millisecond.

38) Chemical synapses are more common than electrical synapses.

39) Glial cells differ from neurons in that they

A) are larger and capable of meiosis.

B) are smaller and capable of mitosis.

C) are found only in the CNS.

D) are found only in the PNS.

E) transmit nerve impulses much more slowly.

40) The nervous system contains more neurons than glial cells.

41) Glial cells help maintain the structure of synapses and they can modify neural transmission.

42) What is the most abundant glial cell in the CNS?

A) Astrocyte

B) Ependymal cell

C) Neurolemmocyte

D) Microglial cell

E) Oligodendrocyte

43) The glial cell that helps to circulate cerebrospinal fluid is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

44) The glial cell that myelinates and insulates axons within the CNS is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

45) The glial cell that helps to form the blood-brain barrier is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

46) The glial cell that myelinates and insulates axons in the peripheral nervous system is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

47) The glial cell that defends the body against pathogens is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

48) The glial cell that protects neuron cell bodies located within ganglia is the

A) satellite cell.

B) ependymal cell.

C) neurolemmocyte.

D) astrocyte.

E) oligodendrocyte.

49) The glial cell with the responsibility of occupying the space left by dead or dying neurons is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

50) The glial cell that provides structural support and organization to the CNS is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

51) The glial cell with perivascular feet that wrap around capillaries in the CNS is the

A) astrocyte.

B) ependymal cell.

C) neurolemmocyte.

D) microglial cell.

E) oligodendrocyte.

52) What do all glial cells have in common?

A) They help to transmit the nerve signals.

B) They transfer blood to the various neurons.

C) They assist neurons in their respective functions.

D) They all attack pathogens.

E) They absorb extra blood and cerebrospinal fluid.

53) The periphery of a myelinating neurolemmocyte that contains its cytoplasm and nucleus is called the ________.

54) The glossy-white appearance of most axons is due to

A) the high lipid content of the myelin sheath.

B) their proximity to light-reflecting cartilage.

C) their proximity to white bone.

D) the white color of the perivascular feet.

E) the covering of ependymal cells.

55) Which is true regarding the action of a neurolemmocyte?

A) Each neurolemmocyte can form a myelin sheath around many axons simultaneously.

B) A neurolemmocyte is responsible for forming part of the blood-brain barrier.

C) Neurolemmocytes function only within the CNS.

D) Each neurolemmocyte can wrap only a 1 mm portion of a single axon.

E) A neurolemmocyte attacks pathogens.

56) Which statement is true regarding the action of an oligodendrocyte?

A) Each oligodendrocyte can form a myelin sheath around many axons simultaneously.

B) An oligodendrocyte is responsible for forming part of the blood-brain barrier.

C) Oligodendrocytes function only within the PNS.

D) Each oligodendrocyte can wrap only a 1-mm portion of a single axon.

E) A neurolemmocyte attacks pathogens.

57) The function of myelin is to

A) block the transmission of a nerve impulse.

B) provide points of attachment for nerve threads.

C) produce faster nerve impulse propagation.

D) produce slow but continuous impulse conduction.

58) Continuous conduction of a nerve impulse occurs only along

A) myelinated axons.

B) dendrites.

C) unmyelinated axons.

D) axons in the PNS.

E) axons in the CNS.

59) Along an axon, the gaps between neurolemmocytes are called neurofibril ________.

60) In the CNS all axons are myelinated, but in the PNS some are myelinated and some are unmyelinated.

61) With damage to nerve fibers, larger distances between the site of damage and the target structure innervated result in ________ chances of successful regeneration.

A) increased

B) decreased

62) Which division of the nervous system shows a greater capacity for regeneration?

A) CNS

B) PNS

63) Following damage to axons nearby, oligodendrocytes

A) secrete growth factors.

B) do not secrete any chemicals.

C) secrete growth-inhibitory molecules.

D) grow their own fibers to occupy the space.

64) Wallerian degeneration involves the breakdown of

A) the segments of axon and myelin sheath between the site of damage and the peripheral effector.

B) the segments of axon and myelin sheath between the site of damage and the cell body.

C) the neurilemma both central and peripheral to the site of trauma.

D) macrophages and microglia that have completed the job of CNS cleanup after trauma.

65) Although severing a peripheral axon leads to some degeneration, the neurilemma remains largely intact.

66) A nerve

A) contains a single axon.

B) is found only in the CNS.

C) carries only sensory information.

D) carries information only toward the PNS.

E) is a cablelike bundle of parallel axons.

67) Which choice correctly orders the connective tissue wrappings of a nerve, beginning at the outermost layer?

A) Perineurium → epineurium → endoneurium

B) Perineurium → endoneurium → epineurium

C) Epineurium → perineurium → endoneurium

D) Epineurium → endoneurium → perineurium

E) Endoneurium → perineurium → epineurium

68) The endoneurium is composed of

A) dense regular connective tissue.

B) simple squamous epithelium.

C) dense irregular connective tissue.

D) areolar connective tissue.

E) pseudostratified nonkeratinized epithelium.

69) The epineurium is composed of

A) dense regular connective tissue.

B) simple squamous epithelium.

C) dense irregular connective tissue.

D) areolar connective tissue.

E) pseudostratified nonkeratinized epithelium.

70) The connective tissue wrapping that surrounds bundles (fascicles) of axons is the

A) epineurium.

B) endoneurium.

C) perineurium.

D) endosteum.

E) periosteum.

71) The type of transport protein that moves a substance down its concentration gradient is a

A) channel.

B) pump.

72) Chemically gated ion channels are mainly found in the ________ segment of a neuron.

A) initial

B) receptive

C) conductive

D) transmissive

73) A neuron's membrane contains more potassium leak channels than sodium leak channels.

74) The axon hillock makes up the ________ segment of a neuron.

75) Contrast chemically gated and voltage-gated channels. How do their functions differ? In which segments of a neuron are they found?

76) The type of voltage-gated channel that possesses an inactivation gate that temporarily closes after the channel is active is the

A) voltage-gated potassium channel.

B) voltage-gated sodium channel.

C) voltage-gated calcium channel.

D) voltage-gated chloride channel.

77) Potassium has a higher concentration

A) inside the cell versus outside the cell, and sodium is also more concentrated inside versus outside the cell.

B) inside the cell versus outside the cell, whereas sodium has a higher concentration outside versus inside the cell.

C) outside the cell versus inside the cell, and sodium is also more concentrated outside versus inside the cell.

D) outside the cell versus inside the cell, whereas sodium has a higher concentration inside versus outside the cell.

78) Negatively charged protein molecules are more prevalent within a neuron's cytosol than in the interstitial fluid.

79) The electrochemical gradient refers to

A) the difference in concentration of a substance between two areas.

B) the difference in electrical charge between two areas.

C) the combination of electrical and chemical gradients between two areas.

D) the resistance a membrane has to allowing any charged chemical to pass through it.

80) According to Ohm's law, current is

A) directly related to both voltage and resistance.

B) directly related to voltage and inversely related to resistance.

C) inversely related to both voltage and resistance.

D) indirectly related to voltage and directly related to resistance.

81) The separation of oppositely charged ionic particles across a resting neuron's membrane results in a potential that is measured as a

A) current.

B) voltage.

C) conductance.

D) resistance.

82) Typically, the resting membrane potential of a neuron is

A) 7 V.

B) 700 mV.

C) −7 V.

D) −70 mV.

E) 0 mV.

83) To measure the resting potential of a neuron, a physiologist would place

A) two electrodes inside the neuron.

B) one microelectrode inside the neuron and another in the interstitial fluid.

C) one electrode inside the cell and another inside another cell.

D) one electrode inside the cell and another outside the body.

84) The most crucial factor determining the resting potential of a neuron is the diffusion of

A) potassium out of the cell through leak channels.

B) potassium into the cell through gated channels.

C) sodium out of the cell through leak channels.

D) sodium into the cell through gated channels.

85) If there were no sodium leak channels, the resting membrane potential of a neuron would be

A) more negative.

B) more positive.

C) the same.

D) 0 mV.

86) Maintenance of appropriate ion concentrations (especially after nerve impulses that involved ion diffusion) is primarily the job of

A) voltage-gated channels.

B) sodium-potassium pumps.

C) chemically gated channels.

D) mechanically gated channels.

87) A depolarization is when the inside of a neuron becomes ________ the resting membrane potential.

A) more negative than

B) less negative than

C) closer to

88) Hyperpolarization of a neuron results from

A) either the entry of an anion or the exit of a cation.

B) the entry of any ion.

C) either the entry of a cation or the exit of an anion.

D) the entrance of either sodium or potassium.

89) Graded potentials generally occur only on the axon of a neuron.

90) A graded potential is one that

A) is all or none (always the same intensity).

B) travels the length of the nerve fiber (is long-distance).

C) varies in size depending on the magnitude of the stimulus (larger voltage change for stronger stimulus).

D) lasts for several seconds after ion channels have opened, closed, and reset.

91) An action potential involves a temporary reversal of polarity across the plasma membrane (that is, the inside of the axon becomes relatively positive compared to the interstitial fluid).

92) Action potentials are generated by the opening of ________ gated channels and they occur on the ________.

A) voltage-, axon

B) voltage-, dendrite

C) chemically, axon

D) chemically, dendrite

93) A postsynaptic potential is a graded potential.

94) When a neurotransmitter opens a chemically gated ion channel that allows sodium to enter the postsynaptic cell, the result is an

A) EPSP.

B) IPSP.

95) As it moves from the tip of a dendrite to the axon hillock, a postsynaptic potential will maintain a constant amplitude.

96) When a neurotransmitter causes the opening of chemically gated potassium channels on the postsynaptic cell, the postsynaptic potential that results is an

A) EPSP, which is a depolarization.

B) EPSP, which is a hyperpolarization

C) IPSP, which is a depolarization.

D) IPSP, which is a hyperpolarization.

97) Some inhibitory neurotransmitters exert their effect by causing the opening of chloride channels, which results in the postsynaptic membrane becoming more negative.

98) The size of an EPSP is independent of the amount of excitatory neurotransmitter that is released by the presynaptic cell.

99) A graph of an EPSP would plot time against a voltage trace that would resemble

A) a hill where the high point approaches the threshold value.

B) a hill where the high point is the farthest away from the threshold value.

C) a valley where the low point approaches the threshold value.

D) a valley where the low point is the farthest away from the threshold value.

100) In neurophysiology, the term "summation" refers to the addition of

A) action potentials at the node of Ranvier.

B) postsynaptic potentials at the initial segment.

C) excitatory neurotransmitter molecules at a receptor.

D) resting membrane potentials in a particular area of the brain.

E) presynaptic hyperpolarizations.

101) When multiple presynaptic neurons release neurotransmitter at various locations onto the postsynaptic neuron at the same time, this results in

A) suprathreshold hyperpolarization.

B) temporal summation.

C) spatial summation.

D) several action potentials.

102) When a single presynaptic neuron repeatedly releases neurotransmitter in a very short period of time, it results in ________ summation in the postsynaptic neuron.

103) The conductive segment of a neuron is its ________, a region that contains many ________ gated channels.

A) axon, voltage-

B) axon, chemically

C) dendrite, voltage-

D) dendrite, chemically

104) Voltage-gated potassium channels in a neuron's axon are triggered to open when membrane potential becomes more negative.

105) When voltage-gated K+ channels open on the conductive segment of a neuron,

A) potassium exits, repolarizing the cell to a negative value.

B) potassium exits, depolarizing the cell to an even more negative value.

C) potassium enters, depolarizing the cell to a positive value.

D) potassium enters, repolarizing the cell to a negative value.

E) potassium enters, repolarizing the cell to a positive value.

106) Voltage-gated sodium channels at a neuron's initial segment are triggered to open when the membrane becomes more positive.

107) The hyperpolarization that occurs at the end of an action potential is due to the prolonged

A) open state of voltage-gated sodium channels.

B) closure of chemically gated sodium channels.

C) open state of voltage-gated potassium channels.

D) closure of voltage-gated potassium channels.

E) open state of chemically gated sodium channels.

108) Which occurs first?

A) Absolute refractory period

B) Relative refractory period

109) As a neuron's refractory period ends, its sodium channels are changing from

A) their resting state to their inactivated state.

B) their inactivated state to their resting state.

C) their resting state to their activated state.

D) their activated state to their resting state.

110) Imagine a genetic mutation that resulted in a malfunctioning inactivation gate in a voltage-gated sodium channel. The defective gate wouldn't always open and close when it should. What functional problems would this cause for the neurons?

111) After an impulse, the ________ refractory period is the time when it is possible to initiate another impulse, but it requires a stronger than usual stimulus.

112) When a nerve impulse reaches the transmissive segment of a neuron,

A) calcium is pumped into the neuron and neurotransmitter diffuses out through channels.

B) calcium is released from the neuron along with neurotransmitter from synaptic vesicles.

C) calcium diffuses into the neuron and neurotransmitter is released by exocytosis.

D) calcium and neurotransmitter diffuse into the synaptic knob.

E) calcium is immediately pumped out of the neuron and vesicles of neurotransmitter undergo phagocytosis.

113) Arrival of an action potential at the synaptic knob results in

A) opening of voltage-gated calcium channels and diffusion of calcium into the synaptic knob.

B) opening of voltage-gated calcium channels and diffusion of calcium out of the synaptic knob to the interstitial fluid.

C) closure of voltage-gated calcium channels in the synaptic knob membrane.

D) opening of chemically gated calcium channels and diffusion of calcium into the synaptic knob.

E) opening of chemically gated calcium channels and diffusion of calcium out of the synaptic knob to the interstitial fluid.

114) Neurotransmitter is released from the synaptic knob by exocytosis, and it then diffuses across the synaptic cleft.

115) In order to trigger the release of neurotransmitter from a neuron terminal, calcium ions

A) exit the synaptic knob through diffusion.

B) bind to proteins on the surface of synaptic vesicles.

C) penetrate the synaptic vesicles and bind to molecules of neurotransmitter.

D) bind to ion channels on the neuron membrane and cause them to open for the transmitter.

116) A nerve impulse travels fastest along ________ axons of ________ diameter.

A) myelinated, small

B) unmyelinated, small

C) myelinated, large

D) unmyelinated, large

117) In a myelinated axon, the greatest concentration of voltage-gated ion channels is in the

A) myelinated regions.

B) neurofibril nodes.

118) Saltatory conduction occurs in

A) myelinated axons, where action potentials occur only at neurofibril nodes.

B) myelinated axons, where action potentials occur only under the myelin sheath.

C) myelinated axons, where action potentials occur continuously down the entire axon.

D) unmyelinated axons, where action potentials occur continuously down the entire axon.

E) the axon terminal, where full-size action potentials occur at the hillock.

119) The slowest category of nerve fibers are the

A) A fibers, and they conduct impulses at 10 meters per second.

B) C fibers, and they conduct impulses at 1 meter per second.

C) D fibers, and they conduct impulses at 0.1 meter per second.

D) C fibers, and they conduct impulses at 100 meters per second.

E) D fibers, and they conduct impulses at 0.01 meter per second.

120) Somatic motor neuron axons fall into the category of

A) A fibers.

B) B fibers.

C) C fibers.

D) D fibers.

121) Catecholamines are a subtype of ________ neurotransmitter.

A) acetylcholine

B) neuropeptide

C) monoamine

D) amino acid

E) soluble gas

122) A neuropeptide is a molecule that is synthesized from an amino acid by the removal of a carboxyl group and the addition of another small functional group such as an amine group.

123) One main category of neurotransmitters is amino acids.

124) Substance P is a neuropeptide that functions in the transmission of pain information to the brain.

125) The monoamine that has functions related to sleep, appetite, cognition, and mood is

A) dopamine.

B) serotonin.

C) norepinephrine.

D) acetylcholine.

E) epinephrine.

126) The primary inhibitory neurotransmitter in the brain is

A) glutamate.

B) valine.

C) GABA.

D) serotonin.

E) serine.

127) One of the ways in which neurotransmitter is removed from the synaptic cleft is

A) endocytosis by the postsynaptic cell.

B) reuptake by the presynaptic cell.

C) phagocytosis by a macrophage.

D) dendritic lassos.

128) The main way acetylcholine is cleared from a synapse is by

A) degradation by an enzyme.

B) uptake by the postsynaptic cell.

C) reuptake by the presynaptic cell.

D) being engulfed by a supporting glial cell.

129) What effect would an acetylcholinesterase inhibitor have on an acetylcholine synapse? Describe how you think it would influence muscle function. What effect do serotonin reuptake inhibitors have on serotonin synapses? Describe how you think they influence mood.

130) ________ is the release of chemicals that locally regulate the response of neurons to neurotransmitters.

131) When a neuromodulator slows the reuptake of a neurotransmitter or causes expression of an increased number of receptors on postsynaptic neurons, the effect is called

A) facilitation.

B) temporal summation.

C) spatial summation.

D) presynaptic potentiation.

E) recruitment.

132) As an axon approaches the cell onto which it will terminate, it generally branches repeatedly into several

A) teloaxons.

B) dendrites.

C) collateral axons.

D) telodendria.

E) neurolemmocytes.

133) Choose the answer that correctly lists, in chronological order, the events involved in synaptic transmission.

a: A nerve impulse reaches the synaptic knob.

b: Neurotransmitter molecules diffuse across the synaptic cleft.

c: A nerve impulse begins in the postsynaptic cell.

d: Neurotransmitter molecules bind to receptors in the postsynaptic cell.

e: A voltage change occurs in the postsynaptic cell.

A) a, c, b, d, e

B) a, b, e, d, c

C) c, b, d, e, a

D) a, b, d, e, c

E) c, a, b, d, e

134) There are two types of synapses, based on mode of communication. What are they?

A) Mechanical and chemical

B) Magnetic and physical

C) Physical and chemical

D) Chemical and electrical

E) Mechanical and electrical

135) Of the two types of synapses, based on mode of communication, which is less common but allows faster signal transmission?

A) Chemical synapse

B) Mechanical synapse

C) Physical synapse

D) Magnetic synapse

E) Electrical synapse

136) Billions of CNS interneurons are grouped in complex patterns called neuronal

A) networks.

B) complexes.

C) pools.

D) meshes.

E) webs.

137) Which is not a type of neuronal pool?

A) Converging

B) Triangular-pre-discharge

C) Diverging

D) Parallel-after-discharge

E) Reverberating

138) The type of neuronal circuit in which several nerve impulses come together at a single postsynaptic neuron is a ________ circuit.

A) converging

B) diverging

C) reverberating

D) parallel-after-discharge