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Block 5 Module 2 (Lec 1 and 2) > Lec 1 and 2 PNS > Flashcards

Lec 1 and 2 PNS Flashcards

1
Q

The peripheral nervous system is composed of ____ and ____ systems

A

Somatic and visceral nervous system

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2
Q

Part of PNS system that innervates the internal organs.

A

Visceral (autonomic) nervous system

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3
Q

Spinal nerves arises from the spinal cord by 2 roots namely: ____ and _____

A

Dorsal and ventral root

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4
Q

Dorsal root contains fibers that convey somatic and visceral _____ (motor or sensory) information to the CNS

A

sensory

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5
Q

Ventral root of spinal nerve contains three fiber components which are the:

1.
2.
3.

These fibres have motor functions.

A
  1. Large diameter axons to the extrafusal muscle
    fibers
  2. Gamma efferents that innervate the intrafusal
    muscle fibers
  3. Preganglionic visceral efferent fibers
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6
Q

The spinal nerve formed by the union of the dorsal and ventral horn is a ______.

A

mixed nerve

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7
Q

The spinal nerve formed by the union of the dorsal and ventral horn is a mixed nerve. This common nerve trunk divides into four branches namely:

1.
2.
3.
4.

A
  1. Dorsal rami to the skin and deep muscles of the back
  2. Ventral rami to the ventrolateral portion of the body wall and extremities
  3. Meningeal ramus to the meninges, blood vessels, and vertebra
  4. Ramus communicans which connects the common spinal trunk with the sympathetic ganglia. Consist of gray and white ramus.
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8
Q 
Cross section of a peripheral nerve discloses round fascicles of nerve fibers separated by connective tissue sheaths. Blood vessels penetrate the connective tissue sheath to nourish the nerve fibers.
• The fascicles contain:
1.
2.
3.
4.
5.
A 
Schwann cells and fibrocytes
Axons
Myelin sheaths
Collagen fibrils of the endoneurium 
Blood vessels
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9
Q

Connective tissue sheath:

  1. __________ - consists of fibrocytes and collagen fibrils which run longitudinal to the nerve fibers
  2. ___________ – divides the nerve into fascicles
  3. ___________ – outermost sheath of peripheral
A
  1. Endoneurium
  2. Perineurium
  3. Epineurium
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10
Q

The Myelin Sheath is a segmented, multilamellar, lipid-rich wrapping of axons formed by the ________.

A

plasma membranes of oligodendrocytes (CNS) or Schwann cells (PNS)

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11
Q

Function of Myelin sheath is to increase speed of conduction by ______.

A

saltatory conduction

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12
Q

Formation (by oligodendrocytes):

  1. Formed by a cell-to-cell interaction in which the axon destined for myelination is recognized by
    proteins on the oligodendrocyte surface
  2. The oligodendrocyte responds by producing a
    flattened, sheet-like process that wraps
    repeatedly around the axon.
  3. As layers of membrane accumulate, all _______ is
    excluded.
  4. The mature sheath consists of layers of ______ (organelle) oligodendrocyte plasma membrane firmly pressed together.
A

cytoplasm

Oligodendrocytes plasma membrane

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13
Q

The spinal and autonomic ganglia are part of the _______ nervous system.

A

peripheral

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14
Q

The ______ contains the cell bodies of the afferent fibers that innervate both somatic and visceral structures. It is purely sensory.

A

spinal ganglion

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15
Q

The _______ ganglion contains efferent visceral fibers. It is purely motor.

A

autonomic

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16
Q

The autonomic ganglion contains______ fibers. It is purely motor.

A

efferent visceral

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17
Q

A purely motor ganglion

A

Autonomic ganglion

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18
Q

A purely sensory ganglion

A

Spinal ganglion

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19
Q

A ______ contains bundles of fibers, either axons or dendrites, surrounded by connective tissue.

A

nerve

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20
Q

Sensory nerves contain only _____ fibers, long dendrites of sensory neurons.

Motor nerves have only ______ fibers, long axons of motor neurons.

A

afferent

efferent

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21
Q

_____ nerves contain both types of fibers.

A

Mixed

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22
Q

There are ___ pairs of segmentally arranged spinal nerves.

A

31

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23
Q 
Classification of Nerve Fibers
Anatomically:
1.
2. 
3.
A

─ Diameter
─ Length
─ Presence or absence of myelin sheath

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24
Q

Classification of Nerve Fibers

Functionally:
1.
2.
3.
4.
5.
A

─ Conduction Velocity
─ Conduction direction; afferent or efferent
─ Type of sensory modality served
─ Type of structure innervated; visceral or
somatic
─ Type of neurotransmitter

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25
Q

True or false

Each pair of spinal nerves innervates asymmetrically paired somites.

A

False

-symmetrically

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26
Q

Each somite differentiates into a ___, ____, and _____.

A

myotome, sclerotome, and a dermatome.

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27
Q

EFFERENT FIBERS OF THE VENTRAL ROOTS innervate________ and some ventral roots contain preganglionic autonomic fibers which pass to autonomic ganglia which in turn give rise to POSTGANGLIONIC FIBERS that innervate ____, ____, and ____.

A

Somatic musculature

blood vessels, smooth muscles, and glandular epithelium.

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28
Q

The cutaneous area supplied by the sensory fibers from a single dorsal root and its ganglion is called a _______.

A

dermatome

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29
Q

During dev’t, metameres migrate distally into the limb buds and arrange themselves to the ____ axis of future limb.

A

long

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30
Q

• During dev’t, metameres migrate distally into the limb buds and arrange themselves to the long axis of future limb.

  • As a consequence of limb dev’t, C4 dermatome comes to lie adjacent to the ___ dermatome
  • The dermatomes of ___ through___ lie in the upper extremity.
  • Dermatomes of ___ and ___ are adjacent posteriorly
A

T2
C5 through T1
L2 and S3

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31
Q

Innervation of:

C2 -

A

occipital protuberance

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32
Q

C3 -

A

supraclavicular fossa

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33
Q

C4

A

Acromioclavicular joint

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34
Q

C5

A

Lateral antecubital fossa

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35
Q

C6

A

Thumb

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36
Q

C7

A

Middle finger

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37
Q

C8

A

Little finger

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38
Q

T1

A

Median antecubital fossa

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39
Q

T2

A

Apex of axilla

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40
Q

T4

A

Nipple line

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41
Q

T10

A

Level of umbilicus

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42
Q

L1

A

Upper anterior thigh

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43
Q

L2

A

Middle anterior thigh

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44
Q

L3

A

Medial femoral condyle

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45
Q

L4

A

Medial malleolus

46
Q

L5

A

3rd MTP joint

47
Q

S1

A

Lateral heel

48
Q

S2

A

Popliteal fossa

49
Q

S3

A

Ischial tuberosity

50
Q

S3 to S5

A

Anogenital region

51
Q

occipital protuberance

52
Q

supraclavicular fossa

53
Q

acromioclavicular joint

54
Q

lateral antecubital fossa

55
Q

thumb

56
Q

middle finger

57
Q

little finger

58
Q

median antecubital fossa

59
Q

apex of axilla

60
Q

nipple line

61
Q

level of umbilicus

62
Q

upper anterior thigh

63
Q

mid anterior thigh

64
Q

medial femoral condyle

65
Q

medial malleolus

66
Q

3rd MTP joint

67
Q

lateral heel

68
Q

popliteal fossa

69
Q

ischial tuberosity

70
Q

anogenital region

71
Q

_________ plexus type – contribution from the fourth cervical is strong and that of the first thoracic is negligible

72
Q

_________ plexus type – fourth cervical does not participate at all but the first thoracic makes a significant contribution

73
Q

(Degeneration type)

In the distal portion, the axon and myelin sheath completely disintegrate and degeneration occurs throughout the length of the fiber including terminal arborization.

A

Anterograde Degeneration

74
Q

Initial Changes in anterograde degeneration

A

Accumulation of mitochondria in the axoplasm at the node of Ranvier, followed by breakdown of the axoplasm and mitochondria.

75
Q

What happens after 12 hrs from injury in anterograde degeneration?

A

The axon becomes swollen and irregular in shape.

76
Q

What happens after a few days in anterograde degeneration?

A

─ The axon begins to breakup into fragments myelin sheath.

─ The myelin sheath also degenerates and fragment after a few days.

77
Q

What happens in the Synaptic Terminal during anterograde degeneration?

A

─ Degenerating synaptic terminals begin to be filled up with electron dense products of degeneration including whorls of neurofilaments that surround swollen disrupted mitochondria.

78
Q

The cell body swells and becomes distended, the nucleus is displaced toward the periphery and the
Nissl bodies undergo dissolution.

A

Retrograde Degeneration

79
Q

The extent and rapidity of changes in rretrograde degeneration depend on _____, ______, and ______.

A

the type of neurons involved,
nature of the lesion
location of the injury

80
Q

4 characteristics of NEURONAL REGENERATION

A
  1. Appearance of the Nissl bodies around the nuclear
    membrane
  2. Swelling of the perikaryon subsides
  3. The nucleus returns to its central position
  4. Nissl bodies are restored to the normal amount and
    distribution
81
Q

Failure of the nerves to regenerate is caused by the __________.

A

inability of the tendrils to find the proper path of re-connection

82
Q

True or false

Skeletal musculature innervated by motor axons in a given spinal root

83
Q

Segmental innervation of skeletal musculature

84
Q

Segmental innervation of skeletal musculature (myotomes) worked out by:
________
________
________

A
  1. Selective stimulation of ventral roots
  2. Study of the pathologic changes which occur in the
    anterior horn cells when a ventral root or motor
    nerve is cut
  3. Study of secondary degeneration of peripheral
    nerve fibers to muscle after central and
    peripheral lesions
85
Q

Majority of muscles innervated with _______ (how many?) ventral roots

A

3 or 4 ventral roots

86
Q

__________ of fibers from individual spinal

cord segments to a specific muscle provides clue to myotonic orgin of skeletal muscle

A

Peripheral projection

87
Q

What spinal segment/s supply/s the motor activity below?

movements of head (by muscles of the neck)

88
Q

movements of diaphragm (phrenic center)

89
Q

Movements of upper extremity

90
Q

Biceps tendon reflex (flexion of forearm on percussion of biceps tendon)

91
Q

Triceps tendon reflex (extension of forearm on percussion of triceps tendon)

92
Q

Radial periosteal reflex (flexion of forearm on percussion of distal radius)

93
Q

Wrist tendon reflex (flexion of fingers on percussion of wrist tendons)

94
Q

Movements of trunk

95
Q

Abdominal superficial reflexes (ipsilateral contraction of subjacent abdominal muscles on stroking the skin of upper, middle, & lower abdomen)
─ upper (epigastric): ____
─ middle: _____
─ lower: _____

A

T6 and aT7
T8 and T9
T10 and T12

96
Q

Movements of lower extremity

97
Q

Cremasteric superficial reflex (elevation of scrotum on stroking skin on inner aspect of thigh)

98
Q

Genital center for ejaculation:
─ smooth muscle: ____
─ skeletal muscle: _____

A

L1 and L2

S3 and S4

99
Q

Vesical center for retention of urine

100
Q

Patellar tendon reflex or knee jerk (extension of leg on percussion of patellar ligament)

101
Q

Gluteal superficial reflex (contraction of glutei on stroking skin over glutei)

102
Q

Plantar superficial reflex (flexion of toes on stroking the sole of foot)

103
Q

Achilles tendon reflex or ankle jerk (plantar flexion of foot on percussion of Achilles tendon)

104
Q

Genital center of erection

105
Q

Vesical center for evacuation of bladder

106
Q

Bulbocavernosus reflex (contraction of bulbocavernosus muscle on pinching penis)

107
Q

Anal reflex (contraction of external rectal sphincter on stroking perianal region)

A

S4, S5 and coccygeal

108
Q

BRACHIAL PLEXUS Roots are mostly derived from _____ primary rami of ___ to ____ spinal nerves

A

ventral

C5 to T1

109
Q

A ________ is the cutaneous area supplied by a single spinal nerve root; the cell bodies are located in dorsal root ganglia.

110
Q

True or false

The dorsal roots contain most afferent fibers, both somatic and visceral.

Block 5 Module 2 (Lec 1 and 2) (1 decks)

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