Chapter 3 Flashcards

1
Q

What are the major divisions of the nervous system?

A

Central nervous system and peripheral nervous system

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2
Q

What is the central nervous system composed of?

A

the brain and spinal cord

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3
Q

What is the peripheral nervous system divided into?

A

sensory (afferent) nerves and motor (efferent) nerves

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4
Q

What do sensory nerves do?

A

informs the CNS about what is going on within and outside the body

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5
Q

What do efferent nerves do?

A

sends info from the CNS to the various tissues, organs, and body systems in response to the signals from the sensory division

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6
Q

What are motor neurons in the motor nerve?

A

neurons that project their axons outside the CNS to directly or indirectly control muscles

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7
Q

What are the two parts of the efferent nervous system?

A

the automatic nervous system and somatic nervous system

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8
Q

What is a neuron?

A

the basic structural unit of the nervous system

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9
Q

What are the 3 regions of neurons?

A

the cell body, dendrites, and axon

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10
Q

What is the axon hillock?

A

a cone-shaped region the cell body tapers into. Has a role in impulse conduction

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11
Q

What are dendrites?

A

the neuron’s receivers

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12
Q

How many axons and dendrites does a neuron have?

A

one axon and many dendrites

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13
Q

How do impulses/action potentials from sensory stimuli enter the neuron?

A

via the dendrites

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14
Q

What do dendrites do after they receive an impulse/action potential?

A

carry the impulse toward the cell body

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15
Q

What does the axon do in the neuron?

A

it’s a transmitter and conducts impulses away from the cell body

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16
Q

What happens at the end of an axon?

A

it splits into numerous end branches

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17
Q

What are the tips of end branches?

A

axon terminals

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18
Q

What are the vesicles in axon terminals filled with?

A

neurotransmitters

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19
Q

Explain how a nerve impulse travels through the neuron.

A

nerve impulses enter the neuron through the dendrites, to a lesser extent through the cell body then the axon hillock. it then travels down the axon and out through the end branches to the axon terminals.

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20
Q

What is excitable tissue?

A

neurons that can respond to various types of stimuli and convert those messages to a nerve impulse

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21
Q

How are nerve impulses started?

A

when a stimulus is strong enough to substantially change the normal electrical charge of a neuron

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22
Q

What happens after a nerve impulse is formed?

A

the signal moves along the neuron, down the axon, and toward another neuron or group of muscle fibers.

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23
Q

Explain the cycle of an electrical signal/nerve impulse

A

The electrical signal for communication between the BRAIN and MUSCLE is generated by a stimulus, then propagated down an axon, and transmitted to the next cell in line

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24
Q

What is the resting potential of the cell membrane of a neuron

A

-70mV

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25
Q

How does the electrical charge work for a cell at resting potential?

A

the electrical charge inside the cell and the one outside of the cell would differ by 70mV. The inside would be negative relative to the outside

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26
Q

What is resting membrane potential (RMP)?

A

the electrical potential difference

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27
Q

What is the RMP caused by?

A

the imbalance in the number of ions inside and outside the cell membrane

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28
Q

When is the membrane polarized?

A

when the charges across the membrane differ

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29
Q

Why is the resting potential of a neuron’s cell membrane 70mV?

A

because of the difference in how potassium and sodium ions move. it’s more positive outside than inside.

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30
Q

The neuron has a high concentration of what on the inside of the membrane?

A

potassium ions (K+)

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31
Q

The neuron has a high concentration of what on the outside of the membrane?

A

sodium ions (Na+)

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32
Q

How is the ion imbalance maintained without the sodium-potassium pump?

A

ions will move to establish equilibrium. some K+ ions will move to the area where they are less concentrated, outside the cell

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33
Q

Why can K+ move more freely in the cell membrane?

A

the cell membrane is more permeable to K+ than Na+

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34
Q

How is the ion imbalance maintained with the sodium-potassium pump?

A

Na+ – K+ – ATPase actively moves potassium ions in and sodium ions out

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35
Q

What are two ways the ion imbalance in a cell membrane are maintained?

A

K+ moving to establish equilibrium and sodium-potassium pumps in neurons

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36
Q

How many ions are moved by the sodium-potassium pumps?

A

3 Na+ ions are moved out of the cell for each 2 K+ ions it brings in

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37
Q

What is the primary function of the sodium-potassium pumps?

A

maintaining a constant RMP of about -70mV

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38
Q

What is the sodium-potassium pumps fueled by?

A

ATP

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39
Q

What is happening when the membrane is depolarized?

A

the inside of the cell becomes less negative making the potential difference across the membrane decrease

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40
Q

What is depolarization?

A

when the inside of a cell becomes more positive

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41
Q

What happens in depolarization?

A

The sodium channels are open. -70mV to 0

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42
Q

What does depolarization cause?

A

movement

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43
Q

What is happening when the membrane is hyperpolarized?

A

the charge difference across the membrane increases, moving from the RMP to an even more negative value

44
Q

What is hyperpolarization?

A

when inside of the cell becomes more negative

45
Q

What is closed and opened in hyperpolarization?

A

sodium channels are closed and potassium is opened. -70mV to -100mV

46
Q

What does hyperpolarization do?

A

stops movement (impulse)

47
Q

What do changes in the membrane control?

A

the signals used to receive, transmit, and integrate information within and between cells

48
Q

What are the two types of signals?

A

graded potentials and action potentials

49
Q

What are graded and action potentials?

A

electrical currents created by the movement of ions

50
Q

What are graded potentials?

A

localized changes in the membrane potential, either depolarization or hyperpolarization. only in one neuron

51
Q

What are graded potentials triggered by?

A

a change in the neuron’s local environment

52
Q

What are action potentials?

A

a rapid and substantial depolarization of the neuron’s membrane. strong enough to move to the next neuron. ONLY depolarization

53
Q

How long do action potentials last?

A

about 1 ms

54
Q

What is happening during an action potential?

A

the membrane potential changes from the RMP to a value of about +30mV and then rapidly returns to its resting value. -70mV to -55mV or less negative/more positive = action potential

55
Q

How does an action potential occur?

A

when sufficient stimulation occurs to cause a depolarization of at least 15 to 20mV, an action potential results

56
Q

What do action potentials begin as?

A

graded potentials

57
Q

What is a threshold?

A

the membrane voltage at which a graded potential becomes an action potential

58
Q

What number is a threshold?

A

-55mV

59
Q

What is the all or none principle?

A

any time depolarization reaches or exceeds the threshold, an action potential will result

60
Q

What is the absolute refractory period?

A

sodium channels are open getting ready to generate an action potential. no new impulses. during depolarization

61
Q

When is repolarization occurring?

A

When the sodium gates are closed and the potassium gates are open

62
Q

What is the relative refractory period?

A

the segment of the axon can potentially respond to a new stimulus, but the stimulus must be of substantially greater magnitude to evoke an action potential. the sodium-potassium pumps is doing its work

63
Q

What will happen if repolarization can occur?

A

sodium channels will reopen if next impulse is strong

64
Q

What two characteristics of a neuron determine how quickly an impulse can pass along an axon?

A

myelination and diameter

65
Q

How does myelination affect an impulse?

A

the myelin sheath is not continuous on the axon so there are gaps that leave the axon uninsulated at different points. the action potential will jump from one node to the next

66
Q

What is saltatory conduction?

A

when an action potential will jump from one node to the next as it traverses a myelinated fiber

67
Q

How does diameter affect an impulse?

A

neurons of larger diameter conduct nerve impulses faster because there is less resistance to local current flow

68
Q

What type of muscle fibers are axons with larger diameters feeding?

A

type 2

69
Q

What is a synapse?

A

junction or gap between neurons

70
Q

How does the signal change from one neuron to another?

A

it changes from electrical to chemical, then back to electrical

71
Q

What does a synapse between two neurons include?

A

the axon terminals of the neuron sending the action potential, receptors of the neuron receiving the action potential, and the space between structures

72
Q

What is a synaptic cleft?

A

a narrow gap that separates the axon terminals and postsynaptic receptors

73
Q

An action potential can be transmitted across a synapse in how many directions?

A

one

74
Q

What does the neuromuscular junction do?

A

allows a-motor neurons to communicate with its muscle fibers

75
Q

What increases the release of Ach?

A

exercise

76
Q

What is the signaling molecule that is shared by the changes induced by training?

A

PGC-1a AKA peroxisome-proliferator-activated receptor – Y coactivator 1a

77
Q

What is the first thing PGC-1a does?

A

increases branching of the presynaptic terminal motor unit

78
Q

What is the second thing the PGC-1a does?

A

increases the number of presynaptic vesicles containing Ach

79
Q

What is the third thing the PGC-1a does?

A

increases the number of Ach receptors on the cell membrane

80
Q

What is the fourth thing the PGC-1a does?

A

decreases the size of the motor end plate

81
Q

How does Ach govern exercise?

A

it stimulates skeletal muscle contractions and mediates parasympathetic nervous system effects

82
Q

How does NE govern exercise?

A

it mediates nervous system effects

83
Q

What are the two major neurotransmitters involved in regulating multiple physiological responses to exercise?

A

Ach and NE

84
Q

What happens when a neurotransmitter binds to a receptor in the postsynaptic membrane?

A

a graded potential is triggered in the post synaptic membrane

85
Q

An incoming pulse can either be

A

excitatory or inhibitory

86
Q

What does an excitatory post synaptic potential (EPSP) do?

A

an excitatory impulse causes depolarization

87
Q

What does an inhibitory post synaptic potential (IPSP) do?

A

an inhibitory impulse causes hyperpolarization

88
Q

What is summation in excitatory post synaptic potential?

A

multiple EPSPs which will cause more depolarizing

89
Q

What happens when threshold depolarization has been reached?

A

an action potential results

90
Q

What is summation in inhibitory post synaptic potential?

A

multiple IPSPs which will cause more hyperpolarizing

91
Q

What is summation in postsynaptic potentials?

A

the accumulation of the individual impulses’ effects

92
Q

What are bundles in the CNS called?

A

tracts or pathways

93
Q

What are bundles in the PNS called?

A

nerves

94
Q

What are the four regions of the CNS?

A

cerebrum, diencephalon, cerebellum, and brain stem

95
Q

What are the three areas in the cerebrum important for exercise?

A

motor cortex, basal ganglia, and primary sensory cortex

96
Q

What are two primary areas in the diencephalon important for exercise?

A

thalamus and hypothalamus

97
Q

What is a major sensory relay center in the diencephalon?

A

the thalamus

98
Q

What is the hypothalamus responsible for?

A

maintaining homeostasis in exercise

99
Q

What does the cerebellum do?

A

controls rapid complex movements, coordinates timing, and sequence of movements

100
Q

What does the cerebellum do with inputs it receives from the primary motor cortex?

A

helps execute and refine movements

101
Q

What accelerates the process that the cerebellum does in our bodies?

A

visuals

102
Q

The brain stem relays info between?

A

the brain and spinal cord

103
Q

Where is reticular formation found?

A

the brain stem

104
Q

What does the reticular formation do?

A

controls cardiovascular and respiratory function

105
Q

What is found in the reticular formation?

A

a pain control center

106
Q

Where is pain modulated?

A

the analgesia system