Chapter 3 pt. 2 Flashcards

1
Q

What is the spinal cord composed of?

A

tracts of nerve fibers that allow two way conduction of nerve impulses

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2
Q

What are the two types of fibers in the spinal cord?

A

afferent fibers (sensory) and efferent fibers (motor)

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3
Q

What do afferent fibers connect?

A

muscle to brain

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4
Q

What do efferent fibers connect?

A

brain to muscle

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5
Q

Sensory division goes from?

A

muscle to brain

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6
Q

What does sensory division in the PNS do?

A

carries sensory info toward the CNS

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7
Q

Sensory division receives info from how many primary types of receptors?

A

5

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8
Q

What are the five sensory receptors?

A

mechanoreceptors, thermoreceptors, nociceptors, photoreceptors, and chemoreceptors

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9
Q

What do mechanoreceptors do?

A

respond to mechanical forces like pressure, touch, vibrations, and stretch

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10
Q

What do thermoreceptors do?

A

respond to changes in temperature

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11
Q

What do nociceptors do?

A

responds to pain

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12
Q

What do photoreceptors do?

A

responds to light to allow vision

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13
Q

What do chemoreceptors do?

A

responds to chemical stimuli from smell, taste, or changes in pH

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14
Q

What are families of sensory receptors that are also mechanoreceptors?

A

joint kinesthetic receptors, muscle spindles, and golgi tendon organs

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15
Q

What are joint kinesthetic receptors sensitive to?

A

sensitive to joint angles and rates of change in the angles

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16
Q

What do joint kinesthetic receptors do?

A

they sense the position and any movement of the joints + proprioception

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17
Q

What do muscle spindles do?

A

senses muscle length and rate of change in length. senses muscle stretch in muscle fibers too

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18
Q

What do golgi tendon organs do?

A

detect the tensions applied by a muscle to its tendon, providing info about the strength of the muscle contraction

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19
Q

What does the autonomic nervous system do?

A

controls the body’s involuntary internal functions

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20
Q

What does the autonomic nervous system help with?

A

heart rate, blood pressure, lung function, and blood distribution

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21
Q

What are the two major divisions of the autonomic nervous system?

A

sympathetic nervous system and parasympathetic nervous system

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22
Q

What is the sympathetic nervous system also known as?

A

fight or flight system

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23
Q

What does the sympathetic nervous system do?

A

prepares the body to face a crisis and sustain its function during the crisis

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24
Q

In the sympathetic nervous system, where is blood going?

A

to the muscles

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25
What is the parasympathetic nervous system?
the body's housekeeping system
26
What does the parasympathetic nervous system do?
carries out processes like digestion, urination, glandular secretion, and conservation of energy
27
When is the parasympathetic system most active?
when one is calm and at rest
28
How are the parasympathetic nervous system's effects different from the sympathetic system?
its affects opposes the sympathetic nervous systems affects
29
What does the parasympathetic nervous system help with?
decreased heart rate, constriction of coronary vessels, and bronchoconstriction
30
How does a sensory stimulus give rise to a motor response?
sensory motor integration
31
What is the first step in the sensory motor integration process?
a sensory stimulus is received by sensory receptors ex: pinprick
32
What is the second step in the sensory motor integration process?
the sensory action potential is transmitted along sensory neurons to the CNS
33
What is the third step in the sensory motor integration process?
the CNS interprets the incoming sensory info and determines which response is most appropriate or reflexively initiates a motor response
34
What is the fourth step in the sensory motor integration process?
the action potentials for the response are transmitted from the CNS along a-motor neurons
35
What is the last step in the sensory motor integration process?
the motor action potential is transmitted to a muscle and a response occurs
36
What is the integration center?
an area where sensory impulses terminate
37
What are reflexes?
responses that are identical each time and occurs before conscious awareness
38
What are motor reflexes?
instant, preprogrammed responses to a given stimulus
39
What is happening during a motor reflex?
the sensory nerves transmit certain action potentials and the body responds instantly and identically
40
What is the fastest mode of response?
a reflex
41
Why is a reflex the fastest mode of response?
the impulse is not transmitted up the spinal cord to the brain before an action occurs
42
What are muscle spindles?
specialized muscle fibers found between regular skeletal muscle fibers
43
Muscle spindles are also referred as?
extrafusal fibers (outside the spindle)
44
What does a muscle spindle consist of on the inside?
4 to 20 small, specialized intrafusal fibers (inside the spindle) and the nerve endings associated with the fibers
45
What are extrafusal fibers controlled by?
a-motor neurons
46
What are intrafusal fibers controlled by?
Y-motor neurons (gamma motor neurons)
47
Why can't the central region of an intrafusal fiber contract?
it contains no or only a few actin and myosin filaments
48
What can the central region of an intrafusal fiber only do?
it can only stretch
49
What excites intrafusal fibers?
the Y-motor neuron
50
What happens when the Y-motor neuron excites the intrafusal fibers?
it prestretches them slightly
51
How does the Y-motor neuron prestretch the intrafusal fibers?
it causes the ends of the fibers to contract making the central region stretch a bit
52
How does the muscle spindle assist in normal muscle action?
when the extrafusal muscle fibers contract and the ends of intrafusal fibers contract, the central region of the muscle spindle stretches giving rise to sensory impulses. this causes the muscle to increase its force production
53
What are golgi tendon organs?
encapsulated sensory receptors through which a small bundle of muscle tendon fibers pass
54
How many muscle fibers are connected to a golgi tendon organs?
5 to 25 muscle fibers
55
What do golgi tendon organs cause?
antagonist contractions
56
How does the golgi tendon organs cause antagonist contractions?
they inhibit contracting (agonist) muscles and excite antagonist muscles
57
How are golgi tendon organs important in resistance exercise?
they help prevent the muscle from developing excessive force during a contraction that may damage the muscle
58
59
What happens once an action potential reaches an a-motor neuron?
it travels the length of the neuron to the neuromuscular junction
60
What happens once an action potential reaches the neuromuscular junction?
the action potential spreads to all muscle fibers innervated by its particular a-motor neuron
61
How many a-motor neurons is a muscle fiber innervated by?
one
62
How many muscle fibers does an a-motor neuron innervate?
up to several thousand muscle fibers depending on the function of the muscle
63
How many muscle fibers do muscles controlling fine movements have per a-motor neuron?
a small number
64
How many muscle fibers do muscles controlling general movements have per a-motor neuron?
many muscle fibers ex: tibialis anterior muscles have innervation ratios of 1:2000
65
What is believed about the characteristics of the a-motor neuron?
the a-motor neuron determines the fiber type in the given motor unit
66
Muscle fibers in a specific motor unit are what?
homogenous with respect to its fiber type. you will not find a motor unit with both type 2 and type 1 fibers.
67
What does it mean when a graded potential is localized?
the depolarization or hyperpolarization does not spread very far along the neuron
68
What does it mean when a graded potential is localized?
the depolarization or hyperpolarization does not spread very far along the neuron
69
What increases muscle strength, power, and mass?
resistance exercise training
70
What increases muscle strength, power, and mass?
resistance exercise training
71
How does a neuron communicate to another neuron?
an action potential
72
What mechanism may contribute to muscle fatigue?
a decline in signal transmission through the neuromuscular junction
73
What mechanism may contribute to muscle fatigue?
a decline in signal transmission through the neuromuscular junction