Chapter 12

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Receptors are parts of the nervous system that allow it to

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Nervous Tissue

154 Terms

1

Receptors are parts of the nervous system that allow it to

Collect information

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2

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

Effectors

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3

Nerves and ganglia are structures found in the

Peripheral nervous system

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4

Which is not a general function of the nervous system

Transporting materials throughout the body

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5

The spinal cord is part of the central nervous system

True

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6

The afferent division of the nervous system is also known as the ____ division

Efferent

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7

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

Transmits impulses from the viscera

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8

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

Somatic sensory

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9

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

Somatic motor

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10

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

Automatic motor

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11

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

Visceral sensory

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12

The motor nervous system is also known as the __________ nervous system.

Efferent

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13

Which is not characteristic of neurons?

High mitotic rate

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14

Conductive activity in a neuron generally causes it to secrete

A specific neurotransmitter that either excites or inhibits its target.

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15

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

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

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16

Which part of the neuron contains the nucleus?

Soma

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17

Where are synaptic knobs located?

At the tips of telodendria

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18

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

Perikaryon

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19

What structures extend into the cytoplasm within a cell body of a neuron is called the

Neurofibrils

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20

Electrical signals are conducted toward the cell body of a neuron by its __________

Dendrites

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21

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

False

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22

Fast axonal transport is

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

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23

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

Fast

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24

Based on structure, the most common type of neuron is the _______ neuron.

Multipolar

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25

Based on function, the vast majority of neurons are

Interneurons

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26

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

Interneurons

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27

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

Interneurons

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28

A bipolar neurons has

One axon and one dendrite extending from the cell body

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29

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

True

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30

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

Anaxonic

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31

A mixed nerve is one that contains both

sensory and motor neurons

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32

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

Cranial

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33

In a mixed nerve

Some axons transmit sensory information and others transmit motor information.

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34

Most commonly, a synapse is made between a

Presynaptic neuron's axon and a postsynaptic neuron's dendrite.

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35

When transmission occurs at a synapse, neurotransmitter is released by

The presynaptic neuron's synaptic knob into the synaptic cleft.

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36

Electrical synapses involve coupling of neurons by

Gap junctions

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37

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

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

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38

Chemical synapses are more common than electrical synapses.

True

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39

Glial cells differ from neurons in that they

Are smaller and capable of mitosis.

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40

The nervous system contains more neurons than glial cells.

False

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41

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

True

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42

What is the most abundant glial cell in the CNS?

Astrocyte

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43

The glial cell that helps to circulate cerebrospinal fluid is the

Ependymal cell

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44

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

Oligodendrocyte

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45

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

Astrocyte

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46

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

neurolemmocyte

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47

The glial cell that defends the body against pathogens is the

Microglial cell

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48

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

Satellite cell

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49

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

Astrocyte

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50

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

Astrocyte

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51

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

Astrocyte

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52

What do all glial cells have in common?

They assist neurons in their respective functions.

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53

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

Neurilemma

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54

The glossy-white appearance of most axons is due to

The high lipid content of the myelin sheath

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55

Which is true regarding the action of a neurolemmocyte?

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

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56

Which statement is true regarding the action of an oligodendrocyte?

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

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57

The function of myelin is to

Produce faster nerve impulse propagation.

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58

Continuous conduction of a nerve impulse occurs only along

Unmyelinated axons

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59

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

Nodes

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60

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

False

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61

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

Decreased

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62

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

PNS

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63

Following damage to axons nearby, oligodendrocytes

Secrete growth-inhibitory molecules.

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64

Wallerian degeneration involves the breakdown of

The segments of axon and myelin sheath between the site of damage and the peripheral effector

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65

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

True

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66

A nerve

Is a cablelike bundle of parallel axons.

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67

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

Epineurium, perineurium, endoneurium

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68

The endoneurium is composed of

Areolar connective tissue

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69

The epineurium is composed of

Dense irregular connective tissue

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70

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

Perineurium

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71

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

Channel

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72

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

Receptive

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73

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

True

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74

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

Initial

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75

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

Voltage-gated sodium channel

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76

Potassium has a higher concentration

Inside the cell versus outside the cell, whereas sodium has a higher concentration outside versus inside the cell

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77

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

True

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78

The electrochemical gradient refers to

The combination of electrical and chemical gradients between two areas

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79

According to Ohm's law, current is

Directly related to voltage and inversely related to resistance

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80

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

Voltage

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81

Typically, the resting membrane potential of a neuron is

-70 mV

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82

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

One microelecrode inside the neuron and another in the interstitial fluid

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83

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

Potassium out of the cell through leak channels

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84

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

More negative

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85

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

Sodium-potassium pumps

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86

A depolarization is when the inside of a neuron becomes _______________ the resting membrane potential

Less negative than

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87

Hyperpolarization of a neuron results from

Either the entry of an anion or the exit of a cation

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88

Graded potenials generally occur only on the axon of a neuron

False

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89

A graded potential is one that

Varies in size depending on the magnitude of the stimulus (larger voltage change for stronger stimulus)

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90

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).

True

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91

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

Voltage-, axon

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92

A postsynaptic potential is a graded potential.

True

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93

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

EPSP

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94

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

False

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95

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

IPSP, which is a hyperpolarization.

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96

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

True

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97

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

False

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98

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

A hill where the high point approaches the threshold value.

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99

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

Postsynaptic potentials at the initial segment

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100

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

Spatial summation

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