CNS part 3 Flashcards

1
Q

what does the somatic motor system of the CNS control

A

skeletal muscles

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2
Q

what does the ANS control

A

involuntary functions

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3
Q

where is the ANS distriubted

A

throughout the visceral organs, CV system, and exocrine glands

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4
Q

what does the reflex arc consist of

A

receptor, sensory neuron, efferent neuron, and effector

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5
Q

upper motor neurons?

A

efferent pathways that relay info from the cerebrum to brainstem or spinal cord

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6
Q

what do upper motor neurons synapse with

A

interneurons

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7
Q

what do UMN control the activity of

A

LMN

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8
Q

if UMN are destroyed, what occurs

A

partial recovery

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9
Q

if LMN are destroyed, what occurs

A

permenant paralysis

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10
Q

where do LMN cell bodies originate? where do their axons go?

A

cell bodies gray matter of spinal cord, but their axons extend to the PNS

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11
Q

what do LMN have a direct influence on

A

muscles

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12
Q

what do we need for voluntary muscle activity

A

UMN stimulation

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13
Q

what is the final common pathway for all voluntary mvmt

A

alpha LMN

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14
Q

what are the 2 types of LMN

A

alpha motor neurons and gamma motor neurons

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15
Q

what do alpha motor neurons innervate

A

extrafusal muscle fibers

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16
Q

what do gamma motor neurons innervate

A

intrafusal muscle fibers

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17
Q

what are alpha motor neurons involved in

A

muscle contraction

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18
Q

what are gamma motor neurons involved in

A

sensing position

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19
Q

what do interneurons connect

A

UMN and LMN

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20
Q

where do alpha motor neurons originate

A

ventral gray matter of spinal cord and brainstem nucleu

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21
Q

what are the 3 inputs to alpha motor neurons what determine which fibers will contract

A

upper motor neurons, spinal interneurons, and sensory neurons

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22
Q

are UMN inhibitory or excitatory

A

inhibitory

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23
Q

what mvmts are UMN involved in?

A

voluntary

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24
Q

are spinal interneurons inhibitory or excitatory

A

they can be either

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25
Q

what are central pattern generators

A

basic motor programs encoded in spinal circuits such as walking

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26
Q

what do sensory neurons from muscle proprioceptors do

A

provide feedback about muscle length and tension

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27
Q

what can damage to LMN cause

A

atrophy, fasciculation, hypotonia, hyporeflexia

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28
Q

what is atrophy?

A

dec in bulk

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29
Q

what is hypotonia?

A

dec in tone of skeletal muscles

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30
Q

what is hyporeflexia?

A

dec muscle stretch

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31
Q

what are fasciculations/fibrillations?

A

involuntary twitches of LMN when denervated motor units discharge spontaneously

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32
Q

what can damage to LMN result in

A

loss of all voluntary and reflex mvmt

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33
Q

ex of pure lower motor neuron lesion?

A

poliomyelitis

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34
Q

what does poliovirus infect

A

motor neuron cell bodies in the ventral horn of spinal cord

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35
Q

what does polio lead to

A

paralysis

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36
Q

amyotrophic lateral sclerosis affects what neurons

A

both upper and lower motor neurons

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37
Q

where does ALS begin

A

cervical spine

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38
Q

what do pt with ALS present with

A

flaccid paresis in upper extremities and spastic paresis in lower extremities

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39
Q

what is lambert eaton myasthenic syndrome

A

antibodies bind to Ca channels and inhibit Ca entry into the nerve terminal

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40
Q

what do aminoglycoside antibiotics do

A

impair Ca channel function

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41
Q

what do clostridium botulinum toxins do

A

cleave presynaptic proteins and prevent NT release at neuromuscular and parasympathetic cholinergic synapses

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42
Q

what occurs at the cellular level in myasthenia gravis

A

autoantibodies bind to the nicotinic AChR and block neurotransmission by inhibiting receptor function and activating complement mediated lysis of postsynaptic membrane

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43
Q

what do somatosensory receptors affect

A

senses of the body

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44
Q

what are mechanoreceptors responsible for

A

position, vibration, vouch

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45
Q

what are nococeptors responsible for

A

pain

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46
Q

what do somatosensory pathways do

A

provide tactile info, guide mvmt, protect

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47
Q

what is a stimulus?

A

distinct type of nrg such as light, sound, heat, mechanical, and chemical

48
Q

receptors are transducers that convert the stimulus energy into what in neurons

A

electrical signals

49
Q

what detects sensation of cold and warm

A

thermoreceptors

50
Q

most numerous type of thermoreceptor

A

cold fibers

51
Q

temps lower that what are considered painful

A

16C or 60F

52
Q

when do warm fibers have their peak response

A

43C or 109 F

53
Q

why does a sudden change in temp transmit initial shock

A

thermoreceptors are rapidly adapting

54
Q

what receptors resond to extreme heat, cold, and pain

A

nociceptors

55
Q

which receptors have a high threshold of activation and are silent unless a noxious stimulus is applied

A

nociceptors

56
Q

what does superficial pain arise from

A

body surface

57
Q

what does deep pain arise from

A

muscles and joints

58
Q

initial pain?

A

sharp highly localized pain that comes on fast bc of myelinated nerve fibers with rapid conduction velocities

59
Q

delayed pain?

A

burning sensation that lasts longer than initial pain. onset is delayed bc unmyelinated neurons have slow conduction velocity

60
Q

where are photoreceptors located

A

rods and cones in retina

61
Q

what are chemoreceptors stimulated by

A

change in chemical composition of environment

62
Q

taste, smell, and visceral receptors are what kind of receptor

A

chemoreceptor

63
Q

what do visceral receptors detect

A

changes in plasma level of O2, pH, and osmolality

64
Q

where are proprioceptors located

A

tendons, muscles, joints

65
Q

what do proprioreceptors do

A

relay info about muscle length and tension

66
Q

what receptors convey sensory info from the skeletal system

A

proprioreceptors

67
Q

dermatome?

A

area of skin supplied with afferent nerve fibers by a single dorsal root

68
Q

sciatica?

A

back pain that radiates down the leg

69
Q

MCC of sciatica?

A

spinal disc herniation that impinges upon a spinal nerve and results in a dermatomal pattern of pain

70
Q

where does L5 pain radiate?

A

back to butt, posterolateral thigh, anterolateral lower leg to the large toe

71
Q

where does S1 pain radiate?

A

back to butt, posterolateral thigh, and calf to the lateral border of the foot

72
Q

merkel discs?

A

sense fine discrimination; slowly adapting and sense pressure

73
Q

meissners corpuscles?

A

sense fine discrimination; rapidly adapting and sense rapid changes in skin contacts

74
Q

are ruffinis endings slow or rapidly adapting?

A

slow

75
Q

what do ruffinis endings detect

A

local stretching of skin

76
Q

are pacinian corpuscles slow or rapidly adapting

A

rapidly

77
Q

what do pacinian corpuscles detect

A

vibration

78
Q

what do hair follicles detect

A

displacement of hair

79
Q

what is visceral pain

A

pain arising from internal organs that is dull, burning, and poorly localized

80
Q

what afferents do visceral pain receptors follow

A

sympathetic

81
Q

what afferents do visceral sensations (like satiety) receptors follow

A

parasympathetic

82
Q

what do noxious stimuli cause

A

referred pain

83
Q

where is referred pain perceived? why do we feel referred pain?

A

perceived on bodys surface; occurs from afferent fibers from the visceral converging on the spinal cord via the dorsal roots

84
Q

where is the ANS located

A

CNS and PNS

85
Q

what are the diff types of muscles/cells in the ANS

A

smooth muscle, cardiac muscle, and gland cells

86
Q

what NS maintains a steady state among visceral/internal organs

A

ANS

87
Q

divisions of the ANS

A

SNS, PSN, and enteric NS

88
Q

are preganglionic neurons myelinated or unmyelinated?

A

myelinated

89
Q

are postganglionic neurons myelinated or unmyelinated?

A

unmyelinated

90
Q

3 functions of the ans

A
  1. maintenance of homeostasis- negative feedback
  2. integration of stress response- fight vs flight
  3. integration of visceral function- coordinate digestive organs
91
Q

what 2 major organs is the ANS associated closely with

A

hypothalamus and pituitary

92
Q

when is the SNS turned on

A

in resp to stress

93
Q

what is the function of the PNS

A

conserve or restore nrg reserves

94
Q

what NS is responsible for the fight or flight response

A

SNS

95
Q

what does the SNS receive innervation from

A

cell bodies from the T1-L2 (thoracolumbar division)

96
Q

what occurs in the body in the fight or flight response

A

sweat secretion, pupil dilation, BV constriction, inc. HR

97
Q

what NS is the rest or repose response

A

PSN

98
Q

what does the PNS receive innervation from

A

cell bodies in the cranial nuclei and sacral region of the spinal cord (craniosacral division)

99
Q

tell me about preganglionic neurons in the PNS

A

they go right to the site; are long

100
Q

tell me about preganglionic neurons in the SNS

A

they are short; postganglionic neurons are longer and go right to the target

101
Q

what receptors interact with the sympathetic preganglionic fibers

A

acetycholine and cholinergic receptors

102
Q

what receptors interact with the sympathetic postganglionic fibers

A

norepinephrine and adrenergic receptors

103
Q

what receptors interact with the parasympathetic pre and post ganglionic fibers

A

acetycholine and cholinergic receptors

104
Q

what is the primary NT released by postganglionic sympathetic neurons

A

norepinepherine

105
Q

the cholinergic postganglionic receptors serve what glands

A

sweat

106
Q

when norepinepherine binds to a target cells, what does the response depend on

A

specific adrenergic receptor type such as alpha 1, or 2 or beta 1, 2 ,or 3

107
Q

what receptors do drugs target

A

adrenergic

108
Q

what does a beta blocker block

A

beta adrenergic receptors

109
Q

what happens to number of neurons as we age?

A

dec

110
Q

what happens to brain size and weight as we age?

A

dec

111
Q

what happens to adherence of dura mater to skull as we age?

A

inc

112
Q

what happens to meninges as we age?

A

fibrosis and thickening

113
Q

what happens to gyri and sulci as we age?

A

gyri narrow and sulci widen which inc size of subarachnoid space

114
Q

cellular changes as we age to the NS

A

deposition of lipofuscin, senile plaques, neurofibrillary tangles, lewy bodies

115
Q

what happens to neural signals to as we age?

A

they slow