Reflexes, Spinal Cord, SCI (10) EXAM 3 Material Flashcards

1
Q

Extrafusal fibers

A

Ordinary skeletal muscle fibers

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2
Q

Intrafusal fibers

A

Muscle spindle

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3
Q

Golgi Tendon Organ

A

lies in the junction of the muscle and tendon

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4
Q

Muscle spindle

A

lies parallel to muscle

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5
Q

What does the muscle spindle do?

A

Provides information on length and rate of length change in muscle
(stretching and how fast)

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6
Q

What type of afferents does the muscle spindle contain?

A

Ia and II afferents

Ia is faster than II

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7
Q

Where does the muscle spindle send information to?

A

Brain and SC (via DCML tract)

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8
Q

What information does the golgi tendon provide?

A

Information regarding muscle contraction

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9
Q

What type of afferents does the golgi tendon organ contain?

A

Ib afferents AND gamma motor neurons

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10
Q

Where does the golgi tendon send information to?

A

Brain and SC (via DCML tract)

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11
Q

Two types of LMNs:

A
  1. Alpha

2. Gamma

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12
Q

How can the alpha motor neurons be stimulated?

A

Ia afferents: from muscle spindle
Ib afferents: from golgi tendon organ (GTO)
UMNs from the brain and/or brainstem

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13
Q

What is the golgi tendon organ sensitive to?

A

Contraction of muscle and muscle tension

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14
Q

T or F: There is motor neuron innervation in the golgi tendon organ?

A

False, no alpha motor neuron innervation

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15
Q

What does stretching the golgi tendon organ cause to happen?

A

Straightens collagen fibers, squeezing and distorting the Ib axons, triggering an action potential

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16
Q

What afferents are firing when a muscle is stretched?

A

Ia and II (muscle spindle)

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17
Q

What afferents are firing when a muscle length is shortened?

A

Ib (golgi tendon organ)

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18
Q

What is the smallest behavioral unit controlled by the NS?

A

Reflexes

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19
Q

What is involuntary and relatively stereotypical?

A

Reflexes

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20
Q

What varies in location of stimulus and strength of stimulus?

A

Reflexes

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21
Q

For a reflex to occur, there must be:

A
  1. Sensory receptor
  2. Afferent (sensory)
  3. Efferent (motor)
  4. Connection between afferent and efferent
  5. Muscles (can’t be damaged)
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22
Q

Can reflexes operate without UMN input?

A

Yes, BUT signals from UMNs typically influence reflexes.

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23
Q

Myotatic Stretch Reflex: Monosynaptic or Dysynaptic?

A

Monosynaptic (one synapse between sensory and motor (alpha) neurons

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24
Q

Myotatic Stretch Reflex: Ia directly excites what motor neurons? And to what muscle (antagonist or agonist)?

A

Alpha motor neurons
Agonist muscle
(Causes contraction)

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25
Q

Myotatic Stretch Reflex: Ia causes inhibition of which muscle (agonist or antagonist)?

A

Antagonist

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26
Q

Myotatic Stretch Reflex: Ia causes inhibition of the antagonist muscle through what?

A

Inhibitory interneuron

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27
Q

Inverse Myotatic Reflex is done through what organ?

A

Golgi Tendon Organ

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28
Q

Inverse Myotatic reflex: Monosynaptic or Disynaptic?

A

Disynaptic

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29
Q

Inverse Myotatic Reflex: Golgi Tendon Organ is most sensitive to what? Causes what to fire?

A

Muscle contraction, causing Ib to fire

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30
Q

Inverse Myotatic Reflex: What inhibits the agonist muscle and through what?

A

Ib inhibits the agonist muscle through an inhibitory interneuron

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31
Q

Inverse Myotatic Reflex: What excites the antagonist muscle and through what?

A

Ib excites the antagonist muscle through an excitatory interneuron.

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32
Q

Cutaneous Reflexes are:

A

Polysynaptic, with interneurons in the reflex arc

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33
Q

In cutaneous reflex, there is:

A
  1. Flexor withdrawal

2. Crossed extension

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34
Q

What is a cutaneous reflex caused by?

A

Cutaneous stimulation

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35
Q

A lesion in the spinal region may interfere with the following:

A
  1. Segmental function

2. Vertical Tract Function

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36
Q

Spinal Region Injury: Segmental Function

A

Interfere with function only at the level of the lesion

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37
Q

Spinal Region Injury: Vertical Tract Function

A

Result in loss of function below the level of the lesion

38
Q

Segmental lesions at spinal cord interferes with function where?

A

Only at the level of the lesion

39
Q

Dermatome

A

Specific area of skin innervated by a single dorsal root

40
Q

Myotome

A

Specific muscle or muscle group innervated by a single ventral root

41
Q

Lesion to Dorsal Root of C5-

Sensory:

A

Loss, atypical

42
Q

Lesion to Dorsal Root of C5-

Motor:

A

Fine

43
Q

Lesion to Dorsal Root of C5-

Reflexes:

A

Areflexia

44
Q

Lesion to Dorsal Root of C5-

Below the level of the lesion:

A

Fine, didnt impact tracts going up and down

45
Q

Lesion to LMNs at C5-

Sensory:

A

Fine

46
Q

Lesion to LMNs at C5-

Motor:

A

Weakness (if some)

Paralysis (if all)

47
Q

Lesion to LMNs at C5-

Reflexes:

A

Areflexia

48
Q

Lesion to LMNs at C5-

Below the level of the lesion:

A

Only have effect at specific segment

49
Q

Lesion to C5 nerve-

Myotome effect

A

Paralysis of C5 myotome (elbow flexors)

50
Q

Lesion to C5 nerve-

Dermatome effect

A

Loss of all sensory information from C5 dermatome

51
Q

Vertical Tract Lesions: Loss of communication where?

A

To and/or from the spinal levels BELOW the lesion

52
Q

Vertical Tract Lesion: Signs of damage occur where?

A

BELOW the level of the lesion

53
Q

Vertical Tract Lesions-

Motor signs:

A

UMN signs (hyper-reflexia, hypertonia, paralysis)

54
Q

Brown Sequard Syndrome: Segmental Loss where?

A

AT level of lesion

55
Q

Brown Sequard Syndrome: Segmental Loss, Motor (C5):

A

Loss of elbow flexors

56
Q

Brown Sequard Syndrome: Segmental Loss, Sensory (C5)

A

Loss of dermatome

57
Q

Brown Sequard Syndrome: Segmental Loss, Reflexes (C5)

A

Areflexia

58
Q

Brown Sequard Syndrome: Vertical Tract Loss where? (C5)

A

BELOW level of lesion

59
Q

Brown Sequard Syndrome: Vertical Tract Loss, Sensory? (C5)

A

STT –> contralateral and below

DCML –> ipsilateral and below

60
Q

Brown Sequard Syndrome: Vertical Tract Loss, Reflexes?(C5)

A

Hyperflexia (same side)

61
Q

Brown Sequard Syndrome: Vertical Tract Loss, Motor?(C5)

A

Paralysis Ipsilateral and below

62
Q

Immediately after spinal cord injury: Bleeding

A

Bleeding into injured areas leads to swelling, which compresses and damages axons

63
Q

Immediately after spinal cord injury: Release of free…

A

Release of free radicals break up cell membranes

64
Q

Immediately after spinal cord injury: What invades the site and damages the tissue?

A

Macrophages

65
Q

Immediately after spinal cord injury: What forms scar tissue?

A

Astrocytes

66
Q

Astrocytes do what in a spinal cord injury immediately after injury?

A

Form scar tissue

67
Q

Immediately after spinal cord injury: Spinal Shock

A

Cord functions below lesion are lost or depressed

68
Q

Areflexia (no reflxes) happens where Immediately after spinal cord injury?

A

(somatic and autonomic) at and below level of injury

69
Q

Within weeks or months after a spinal cord injury:

A

Most people experience some recovery of function in the cord

70
Q

Within weeks or months after a spinal cord injury: Muscle tone changes to

A

hypertonicity and hyperactive reflexes (below the level of the lesion)

71
Q

Within weeks or months after a spinal cord injury: Are there sensory, motor and autonomic impairments? If so, where?

A

Yes, below the level of the lesion

72
Q

Within weeks or months after a spinal cord injury: does the neurologic deficit change or stay the same?

A

Once the lesion is stable (no more bleeding, etc) the neurologic deficit does not change

73
Q

Tetraplegia:

A

Loss or impairment in motor and/or sensory function in the cervical segments of the spinal cord resulting in functional impairment in the arms, trunk, legs and pelvic organs

74
Q

Paraplegia:

A

Loss or impairment in motor and/or sensory function in the thoracic, lumbar or sacral segments of the cord resulting in impairment in the trunk, legs and pelvic organs and SPARING of the ARMS

75
Q

Loss or impairment in motor and/or sensory function in the thoracic, lumbar or sacral segments of the cord resulting in impairment in the trunk, legs and pelvic organs and SPARING of the ARMS

A

Paraplegia

76
Q

Loss or impairment in motor and/or sensory function in the cervical segments of the spinal cord resulting in functional impairment in the arms, trunk, legs and pelvic organs

A

Tetraplegia

77
Q

Spinal cord injuries are classified by two criteria:

A
  1. Whether the injury is complete or incomplete

2. The neurological level of injury

78
Q

Complete SC injury:

A

A total lack of sensory and motor function in the lowest sacral segment

79
Q

A total lack of sensory and motor function in the lowest sacral segment

A

Complete SC Injury

80
Q

Incomplete SC Injury:

A

Preservation of sensory and/or motor function in the lowest sacral segment

81
Q

Preservation of sensory and/or motor function in the lowest sacral segment

A

Incomplete SC Injury

82
Q

What is the term used by OTs and PTs; the lowest segment at which strength of key muscles is grade 3+ of 5 or above on manual muscle testing and pain sensation is intact?

A

Functional level

83
Q

Neurologic Level:

A

The most caudal point on the spinal cord with typical sensory and motor function bilaterally.

84
Q

The most caudal point on the spinal cord with typical sensory and motor function bilaterally.

A

Neurologic Level

85
Q

Is it unusual to have a discrepancy between the lowest typical motor level and the lowest typical sensory level?

A

No, it is not unusual.

86
Q

What determines sensory level?

A

Dermatomes

87
Q

Key muscles controlled at: C5

What are they important for?

A

Biceps and Deltoid

Important in eating, facial care, brushing teeth

88
Q

Key muscles controlled at: C6

What are they important for?

A

Wrist extensors

Grasp / Tenodesis

89
Q

Key muscles controlled at: C7

What are they important for?

A

Elbow extensors

Transferring from chair to wheelchair

90
Q

Key muscles controlled at: C8-T1

What are they important for?

A

Finger flexors and finger abductors

Grasp

91
Q

SCI Prognosis:

A

Hard to predict (variable)

92
Q

SCI Prognosis: Axons

A

Axons in spinal cord fo not functionally regenerate