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Tim's Cards > Neuro3 > Flashcards

Neuro3 Flashcards

1
Q

Where, in the brain, is the decision to move (somatic motor) made?

A

Heteromodal association cortices

prefrontal, parietotemporal, or limbic

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2
Q

Where, in the brain, are the cortical motor planning regions?

A

Premotor cortex
Supplementary motor cortex
Frontal eye fields
Broca’s area

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3
Q

What occurs after motor planning decision has been made?

A

Control circuits refine and assist with execution

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4
Q

Where are the motor control circuits?

A

Primary motor cortex, cerebellum, and basal ganglia

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5
Q

What are 7 primary descending motor pathways?

A 
Corticospinal
Corticobulbar
Reticulospinal
Rubrospinal
Vestibulospinal
Tectospinal
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6
Q

The descending motor neurons are UPN/LMN?

A

UPN’s

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7
Q

What to the descending pathway axons synapse with?

A

Interneurons (in the gray matter) and LMN’s in the Ventral Horns

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8
Q

In most of the body, the LMN synapse is in the ______, but cranial nn. synapse in the ______.

A

Ventral horns of the spinal tract

In the nuclei of the brain.

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9
Q

From what supra spinal structures do descending pathways originate?

A

Cortex and brainstem (neuronal cell bodies)

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10
Q

T/F
Descending pathways usually synapse directly (monosynaptically) onto Alpha/Gamma MN’s in ventral horn of the spinal cord and cranial motor nuclei.

A

False.

Most (a majority) synapse with interneurons in the spinal cord.

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11
Q

What other input do alpha and gamma MN’s receive?

A

segmental inputs from peripheral afferents

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12
Q

Descending motor pathways can be both/and?

A

Excitatory
Inhibitory

(these pathways shut off certain mm.’s and activate others)

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13
Q

What dictates the excitatory/inhibitory make-up of these descending motor pathways?

A

spatial and temporal summation with thousands of inhibitory/excitatory interneurons.

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14
Q

The alpha/gamma motor neurons are considered to be…

A

LMN’s

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15
Q

The descending pathways, along with the somas they arise from, are considered to be…

A

UPN’s

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16
Q

What is the largest and clinically most important spinal tract?

A

The Corticospinal Tract

aka - pyramidal tract

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17
Q

Where do the axons of the primary motor tract originate?

A

From somas mostly in the primary motor cortex

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18
Q

Describe the pathway of the Corticospinal Tract from the brain to spinal cord.

A

Primary motor cortex > Corona Radiata > Internal Capsule > Cerebral peduncles > Pyramids

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19
Q

What percentage of fibers from the Corticospinal tract decussate in the medullary pyramids?

A

85-90%

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20
Q

Where do the crossed (85-90%) axons travel through the spinal cord?

A

Lateral Corticospinal Tract

lateral funiculus

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21
Q

What percentage of corticospinal tract fibers have monosynaptic connections?

A

3-5%

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22
Q

Where do the uncrossed (10-15%) fibers in the corticospinal tract descend?

A

Anterior Corticospinal tract

anterior funiculus

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23
Q

What tract is regarded as the descending pathway most concerned with voluntary, discrete, skilled movements?

A

Lateral Corticospinal tract

the crossed one in the majority

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24
Q

What tract controls bilateral axial musculature?

A

Anterior Corticospinal tract

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25
Q

What do Corticobulbar tracts innervate?

A

Cranial nn.’s

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26
Q

Describe the general pathway of a Corticobulbar tract.

A

Somas of motor cortex > corona radiata > internal capsule > cerebral peduncles > cranial nn.’s

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27
Q

Which CN’s are innervated by Corticobulbar tracts?

A 
III
IV
V
VI
VII
IX
X
XI
XII
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28
Q

Which CN’s aren’t innervated by Corticobulbar tracts?

A

I, II, VIII

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29
Q

What Corticobulbar tract is NOT crossed?

A

VII - facial nucleus

is bilateral

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30
Q

What are 2 functions of the Rubrospinal Tract?

A

Skilled dextrous movements of the upper extremity

Alternate route for achieving voluntary movement

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31
Q

Describe the pathway of the Rubrospinal Tract.

A

Cerebral Cortex and Cerebellum > Red nucleus > cross in Ventral Tegmentum as exit > Lateral funiculus

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32
Q

Where, specifically, does the Rubrospinal tract run in the spine?

A

Just anterior to the Lateral Corticospinal Tract

in lateral funiculus

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33
Q

What are the 2 Reticulospinal Tracts?

A

Pontine

Medullary

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34
Q

Where are the reticular spinal formation regions?

A

Pons and Medulla

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35
Q

What is the Medullary Reticulospinal tract also called, and what is its function?

A

aka Lateral Reticulospinal Tract

inhibits lower extremity extensors/facilitates flexors

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36
Q

What does the medullary reticulospinal tract do in terms of tone to the lower extremities?

A

Reduces muscle tone

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37
Q

T/F

The medullary reticulospinal tract is crossed.

A

False

It descends both crossed and uncrossed

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38
Q

The Pontine reticulospinal tract is also called..

A

aka Medial reticulospinal tract

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39
Q

Is the Pontine reticulospinal tract mostly crossed or uncrossed?

A

Mostly UNcrossed

so they synapse ipsilaterally

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40
Q

What is the target of the Pontine reticulospinal tract?

A

Lower extremity extensors (alpha and gamma)

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41
Q

Does the Pontine reticulospinal tract increase or decrease tone?

A

Increases muscle tone

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42
Q

What are the 2 Vestibulospinal tracts?

A

LVST (lateral)

MVST (medial)

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43
Q

The LVST and MVST can be thought of as pathways that counteract what force?

A

Gravity (they are postural)

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44
Q

What are 2 inputs to the Vestibular nuclei?

A

VIII and the cerebellum

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45
Q

What is the function of the Ascending nuclei of the vestibulospinal tract?

A

The vestibuloocular reflex

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46
Q

Where does the vestibuloocular reflex travel, and what does it coordinate?

A

Ascending portion of the MLF (medial longitudinal fasciculus)

Eye and head movements

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47
Q

From whence does the LVST arise?

A

Deiter’s Nucleus

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48
Q

Does the LVST pathway descend crossed or uncrossed?

A

UNcrossed

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49
Q

What pathway in the spinal cord does the LVST use, and where does it terminate?

A

Anterior funiculus

All spinal levels

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50
Q

What mm.’s does the LVST facilitate?

A

LE extensors

UE flexors

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51
Q

LVST is considered the primary….

A

Antigravity pathway

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52
Q

What is the primary function of the MVST?

A

Inhibit UE extensors
Facilitate UE flexors

(this is antigravity for the upper extremities)

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53
Q

Which spinal tract is involved in turning your head at something novel?

A

Tectospinal tract

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54
Q

Tectospinal tract pathway:

A

cell bodies in superior colliculus of midbrain > Tegmentum cross > travels with MVST to upper cervical spinal cord > turns head and neck

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55
Q

What do descending pathways terminate with?

A

interneurons and ventral horn motor neurons at different spinal levels.

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56
Q

What is the pathway of an LMN?

A

Ventral horn > ventral root > spinal root and peripheral nn.’s innervating m.

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57
Q

T/F

mm.’s are innervated by a single spinal level.

A

False.

Multiple levels go into many (larger) mm.’s

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58
Q

What happens if only 1 or 2 ventral roots are damaged?

A

Paresis (muscle weakening)

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59
Q

When does paralysis occur?

A

Either all ventral roots innervating a muscle are destroyed or UMN’s damaged by a stroke.

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60
Q

What is the diaphragm innervated by?

A

C3-5

meaning lesion above C3 leaves pt on ventilator
345 stay alive

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61
Q

T/F

Most spinal cord lesions affect bowel and bladder.

A

True

these are low (S2-4)

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62
Q

What motor neurons have large diameter, travel fast, and innervate extrafusal (motor unit) muscle?

A

Alpha MN

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63
Q

What motor neurons travel slow, have a small diameter, and innervate muscle spindle?

A

Gamma MN

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64
Q

Are Gamma MN’s myelinated?

A

yes. but not as thick as alphas

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65
Q

What are the two types of autonomic fibers?

A

B-motor (pre-ganglionic) lightly myelinated
C-motor (post-ganglionic) unmyelinated

(told us to cross this question/table off)

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66
Q

What do Gamma MN’s do to muscle, say, before a race?

A

Set tone. Gamma’s fire a lot in response to anticipated exertion. Once exertion begins, Alpha MN’s kick in.

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67
Q

What are the 5 separate nuclei that make up the basal ganglia?

A 
Caudate
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra (pars reticula and pars compacta)
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68
Q

What separates the caudate and the putamen?

A

The internal capsule

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69
Q

What are the two parts of the globus pallidus?

A

Externa and Interna

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70
Q

Is the nucleus Accumbens considered to be part of the basal ganglia?

A

Some think this is the 6th nuclei

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71
Q

Caudate + Putamen =

A

Striatum (or neostriatum)

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72
Q

Caudate + Putamen + Globus =

A

Corpus striatum

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73
Q

Putamen + Globus =

A

Lenticulate nucleus

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74
Q

What two parts of the brain are the basal ganglia highly connected to?

A

Cortex and the Thalamus

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75
Q

How many “channels” have been identified in the basal ganglia?

A

4

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76
Q

What are some symptoms of lesions to the basal ganglia?

A

Tremor
Rigidity
Difficulty initiating voluntary movements
Bradykinesia (slow movement)
Ballismus (jerky motions)
Choreoathetoid movements (inlvoluntary)

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77
Q

What are the 4 basal ganglia channels?

A

Occulomotor (eye movements)
Prefrontal (cognitive)
Limbic (emotional)
Motor

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78
Q

Do the basal ganglia have direct connections to the motor neurons in the spinal cord?

A

NO.

stimulation of BG neurons does not directly cause movements (must be a relay area)

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79
Q

Do lesions of the Basal Ganglia cause paralysis?

A

NO

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80
Q

What function is the basal ganglia best know for?

A

Motor

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81
Q

What 4 specific functions does the motor channel have in the basal ganglia?

A

Formulation of general motor plans
Execution of specific motor plans
Scaling of motor intensity
Automatic execution of learned motor plans

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82
Q

What does dysfunction of the Formulation component of the Motor channel in basal ganglia cause?

A

Isolated motor acts only

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83
Q

What does dysfunction in the Scaling component of the Motor channel in basal ganglia cause?

A

Movement at inappropriate rates, amplitudes, and duration

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84
Q

What does a dysfunction in the Automatic execution component of the Motor channel in basal ganglia cause?

A

Much more mental effort must be applied to handwriting, tying shoes, etc.

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85
Q

What channel in the basal ganglia is implicated in motivation?

A

Limbic

also emotion

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86
Q

Where do the outputs of the basal ganglia (specifically the corpus striatum) go?

A

Cortex

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87
Q

Where are the main inputs to the basal ganglia found?

Where do these inputs originate?

A

Caudate and Putamen (striatum/neostriatum)

Cortex and Thalamus

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88
Q

Are the inputs to the Striatum (caudate and putamen) excitatory or inhibitory?

A

Excitatory

glutamatergic

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89
Q

Inputs to the Substantia Nigra pars compacta are…

A

Domaninergic

90
Q

Where are the main outputs from the Basal Ganglia?

A

Globus Pallidus Interna

Substantia Nigra pars Reticula

91
Q

Are the main outputs from the Basal Ganglia excitatory or inhibitory?
Where do they go?

A

Inhibitory (GABAergic)

VL & VA of Thalamus, reticular formation, and superior colliculus

92
Q

What other neurons in the Striatum (caudate and putamen) also play an important role in BG function?

A

Acetylcholinergic

93
Q

What are the 2 main pathways of functional circuitry in the BG, and what modulates them?

A

Direct (excitatory) and Indirect (inhibitory)

Substantia Nigra circuit modulates.

94
Q

What is the end result of Direct Pathway stimulation for the motor, prefrontal, and limbic channels?

A

Increased movement
Increased cognitive function
Increased emotions

95
Q

Direct pathway of the BG:

A

Cortex (excitatory) > Caudate/Putamen (Inhibitory) > GPi/SNr turned off > Thalamus excitation from other stimuli > cortical stimulation

The Globus pallidus interna and Substantia Nigra can no longer inhibit the Thalamus, opening it to other stimuli

96
Q

The Direct Pathway of the BG is excitatory/inhibitory?

A

Excitatory

97
Q

The Indirect Pathway of the BG is excitatory/inhibitory?

A

Inhibitory

98
Q

What is the end result of Indirect Pathway stimulation in the BG for the motor, prefrontal, and limbic channels?

A

Decreased movement, cognitive function, and emotions

99
Q

Indirect pathway of the BG:

A

Cortex (excitatory) > Caudate/Putamen (inhibitory) > Globus Pallidus Externa

GPe can no longer inhibit the Subthalamic nuclei

Subthalamic nuclei (now excited by other input) > Globus Pallidus Interna/Substantia Nigra pars reticulata

GPi/SNr now excited for inhibitory action of Thalamus

Thalamus (now inhibited) > BLOCKS thalamic excitation of the cortex

100
Q

SNc stands for:

A

Substantia Nigra pars compacta

101
Q

What is the neurotransmitter for the SNc (nigrostriatal) pathway?

A

dopamine

102
Q

Dopamine is _______ to the Direct pathway neurons in the Caudate/Putamen and ________ to the Indirect pathway of the Caudate/Putamen.

A

Excitatory

Inhibitory

103
Q

What is the downstream effect of the nigrostriatal (SNc) pathway firing ?

A

Excitation of the direct pathway
Inhibition of the indirect pathway

so, increased movement, emotions, and cognitive functions

104
Q

Which pathway has D1 receptors?

A

Direct

105
Q

Which pathway has D2 receptors?

A

Indirect

106
Q

Do lesions of the basal ganglia cause paralysis?

A

NO

107
Q

What is Bradykinesia

A

slow movements

cardinal sign of parkinson’s

108
Q

What is Athetosis?

What is it associated with?

A

involuntary twisting movements

Huntington’s disease, perinatal hypoxia, antipsychotic meds, anitemetic meds, Levadopa

109
Q

What is Chorea?

What is it associated with?

A

Involuntary fluid (dancelike) movements

Huntington’s disease, perinatal hypoxia, antipsychotic meds, anitemetic meds, Levadopa, infarct/focal lesions of basal ganglia, lupus

110
Q

What causes Ballismus?

A

usually unilateral lesion causing contralateral, involuntary, large flinging movements

111
Q

T/F

Tremors usually vary in frequency

A

False

Tremors usually have specific frequency of movement

112
Q

What is the difference between Rigidity and Dystonia?

A

Rigidity is resistance to passive movement of limb

Dystonia refers to the assumption of distorted positions in limbs, trunk, or face.

113
Q

What lesions of the BG cause Bradykinesia and Akinesia?

A

Substantia Nigra and Globus Pallidus Externa

114
Q

If a lesion takes out the Putamen (specifically the Indirect pathway), what results?

A

Hyperkinesia
Chorea
Athetosis

115
Q

What do lesions of the Caudate nucleus cause?

A

Few movement issues

but, cognitive, emotional, and complex behaviors affected

116
Q

What does a lesion in the Subthalamic nucleus cause?

A

Hemibalismus

117
Q

What causes the abnormal movements of PD?

A

Removal of inhibitory influences on them

118
Q

What are the 4 cardinal features of PD?

A

Tremor
Rigidity
Bradykinesia
Postural instability

119
Q

T/F

PD tremors mostly occur when at rest

A

True,

although some pts have action tremor as well (this is tremor during movement rather than at rest)

120
Q

What 2 types of rigidity are expressed in PD?

A

lead pipe and cog wheel

121
Q

What is the most disabling feature of PD?

A

Bradykinesia

122
Q

What are the 3 main pharmacological treatments for PD and how do they work?

A

Monoamine oxidase inhibitors (prevents breakdown of dopamine)

Dopamine agonist drugs (mimics dopamine)

L-DOPA (precursor to dopamine that crosses BBB)

123
Q

Why would a DOPA decarboxylase inhibitor (drug called Sinemet) benefit recipients of L-DOPA?

A

It prevents L-DOPA conversion to dopamine in the plasma, increasing efficiency of delivery

124
Q

What is the general term for movements indicating the failure of L-DOPA?

A

dyskinesias

including head bobbing, lip smacking, tongue thrusting, etc

125
Q

What are 2 surgical treatments for PD?

A

Deep Brain Stimulation

Ablations (surgical lesions)

126
Q

What type of charge does Deep Brain Stimulation deliver?

What does it do?

A

Continuous

reduces discharge of action potentials and rebalances control messages

127
Q

Where is the electrode placed in DBS for disabling dyskinesias and tremor?

A

Globus Pallidus

128
Q

Where is the electrode placed in DBS to reduce bradykinesia, tremor, and rigidity?

A

Subthalamic nucleus

129
Q

Does successful DBS alleviate all the symptoms of PD?

A

No. Only some symptoms, and doesn’t slow progression of disease.

130
Q

What are the 2 ablations (surgical lesions) used to treat PD?

A

Thalamotomy (small area of thalamus to treat tremor)

Pallidotomy (globus pallidus to treat akinesia)

131
Q

What is a primary symptom of Huntington’s disease?

A

Chorea - uncontrolled, rapid, dance-like

132
Q

What causes the symptoms of Huntington’s?

A

Loss of cholinergic and GABA-ergic neurons in the striatum (causes choreiform movements)
Loss of cortical cells thought to cause impaired cog. functions and dementia

133
Q

What disorder is caused by vascular infarct, hemorrhage, or tumor of the subthalamic nuc.?

A

Ballism or Hemiballism

134
Q

Does the cerebellum have any direct connections with spinal cord ventral horn motor neurons?

A

NO

135
Q

What type of sensory input does the Cerebellum constantly receive?

A

body position, rate of movement, muscle length/force

136
Q

What are 3 symptoms of cerebellar dysfunction?

A

Ataxia (loss of full control of body movements)
Hypotonia (low muscle tone)
Intention tremors (loss of muscle synergy)

137
Q

Name 4 general functions of the cerebellum?

A

Compare actual/intended movements
Plan sequential movements
Learn coordinated movements
Produce synergy of movement

138
Q

What separates the anterior and posterior lobes of the cerebellum?

A

Primary Fissure

139
Q

What makes up the flocculonodular lobe?

A

2 flocculi

1 nodulus

140
Q

What structure lies lateral to the nodulus and medial to the flocculi?

A

Cerebellar tonsils

141
Q

Name 4 deep cerebellar nuclei and their targets:

A

Dentate (cerebrocerebellum)
Globose (spinocerebellum)
Emboliform (spinocerebellum)
Fastigial (vestibulocerebellum)

142
Q

What is the main output pathway of the cerebellum?

A

Superior Cerebellar peduncle

143
Q

What is the main input pathway of the cerebellum?

A

Middle cerebellar peduncle

144
Q

What is the pathway of both input and output in the cerebellum?

A

Inferior peduncle

145
Q

What are the two types of input fibers to the cerebellum?

A

Mossy fibers

Climbing fibers

146
Q

Where do cortico-ponto-cerebellar tract fibers enter the cerebellum?

A

middle cerebellar peduncle

147
Q

Where do dorsal and anterior spinocerebellar tract fibers enter the cerebellum?

A 
inferior peduncle (DCST)
superior cerebellar peduncle
148
Q

What pathway is used by axons in the dorsal spinocerebellar tract to enter the cerebellum?

A

Inferior peduncle

149
Q

Fibers going through the Pons to the cerebellum are termed _______ and fibers going through the Olivary are termed ______.

A

Mossy

Climbing

150
Q

How many spinocerebellar tracts are there?

A

4

151
Q

What are the 4 spinocerebellar tracts and what peduncle receives their inputs?

A

Dorsal - Inferior peduncle
Ventral - Superior peduncle

Spinocuneocerebellar - cuneate nuclei/inferior peduncle
Rostral spinocerebellar - inferior AND superior peduncle

152
Q

Where does the vestibular nerve enter the cerebellum?

A

Inferior peduncle

153
Q

Climbing fibers entering the cerebellum via the inferior olivary nucleus receive inputs from where?

A

cortex, basal ganglia, red nucleus, extrapyramidal pathways

154
Q

What peduncle is used by climbing fibers?

A

Inferior cerebellar peduncle

155
Q

What is the function of the climbing fibers going through the olivary nucleus?

A

error correction and timing motor tasks

156
Q

Lesions to the cerebellum cause ipsilateral/contralateral deficits?

A

Ipsilateral

157
Q

What are the 3 cellular layers of the cerebellum?

A

Molecular
Purkinje
Granular

158
Q

What 4 components make up the molecular layer of the cerebellar cortex?

A

Stellate cells
Basket cells
Parallel fibers
Dendrites of purkinje cells

159
Q

What three components make up the Granular cell layer?

A

granule cells
Golgi cells
glomerulus

160
Q

What are the 3 functional divisions of the cerebellum?

A

Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum

161
Q

Anatomically, what makes up the vestibulocerebellum?

A

Flocculonodular lobe

162
Q

Vestibulocerebellum:

Inputs/Outputs/Function

A

Inner ear/visual system via Inferior cerebellar peduncle

Fastigial nucleus > superior/inferior cerebellar peduncles > vestibular nuclei

Equilibrium, eye and head movements, posture

163
Q

Spinocerebellum:

Inputs/Outputs/Function

A

Spinal cord via superior/inferior peduncles

globose/emboliform nuclei > superior peduncle > reticular formation > contralateral thalamus > contralateral red nucleus

controls ongoing movements/innervates muscle spindles

164
Q

What, anatomically, makes up the spinocerebellum?

A

Part of Vermis and part of cortices just lateral to Vermis

165
Q

Where, anatomically, is the cerebrocerebellum?

A

Lateral cerebellar cortices

166
Q

What is the input to the cerebrocerebellum?

A

cerebral cortex via middle peduncle

167
Q

What is the output of the cerebrocerebellum?

A

Dentate nuc. > superior cerebellar peduncle > contralateral thalamus

168
Q

What is the function of the cerebrocerebellum?

A

Formulation of motor plans and initiation of movements

169
Q

What are three major signs of cerebellar dysfunction?

A

Hypotonia
Disequilibrium
Dyssynergia (there are 8 types listed)

170
Q

What should you relate cerebellar damage to?

A

Being drunk
alcohol affects cerebellar.
Think roadside test for clinical considerations

171
Q

What are 3 less common terms to classify sensory receptors?

A

Interoceptors (within body)
Proprioceptors (body position)
Exteroceptors (arise outside body)

172
Q

Name 5 types of receptors:

A 
Chemo
Photo
Thermo
Mechano
Noci
173
Q

Receptors are, by definition…

A

Transducers

translate energy and lie at border between outside and inside

174
Q

T/F

Some receptors are ends of a nerve, some use second messenger systems to stimulate a nerve.

A

True

175
Q

What do receptor normally require in order to propagate an action potential?

A

Spatial and Temporal summation - graded - this fires the receptor potential

176
Q

What are the two basic structural categories of cutaneous receptors?

A

Encapsulated

non-Encapsulated

177
Q

Do all receptors show adaptation to stimulus?

A

Yes.

Although some rapid, some slow.

178
Q

What class of nerve makes up free nerve endings?

A 
Group III (A-delta) lightly myelinated   
or    Group IV (C) unmyelinated
179
Q

What class of nerve makes up Hair receptors?

A

Group III (A-delta) lightly myelinated

180
Q

What class of nerve are Merkel’s tactile disks?

A

A-beta myelinated

mechanoreceptor

181
Q

Where do you find a high density of Meissner’s corpuscles and what class of nerve innervates them?

A

Fingertips

A-beta myelinated axons

182
Q

What type of nerve is good at sensing vibration and is wrapped in layers of lamellae?

A

Pacinian

183
Q

Pacinian corpuscles are innervated by what class of nerve?

A

A-beta myelinated

184
Q

What class nerve makes up Ruffini endings?

A

A-beta myelinated

senses maintained pressure (this is the deep one)

185
Q

How is localization of a stimulus facilitated?

A

Lateral inhibition

186
Q

What are 4 types of proprioceptors?

A

Joint
Muscle spindle
Golgi Tendon Organ
Cutaneous mechanoreceptors

187
Q

What 4 types of endings make up joint receptors?

A

Free
Ruffini’s
Pacinian corpuscles
Ligament receptors

188
Q

Skeletal muscle fibers aka

Muscle spindle fibers aka

A

Extrafusal

Intrafusal

189
Q

What are two terms used to describe intrafusal fibers depending on the arrangement of their nuclei?

A

Nuclear bag

Nuclear chain

190
Q

What nerve class innervates the nuclear chain fibers?

A

Group II afferent (flower spray)

191
Q

What nerve class innervates the nuclear bag fibers?

A

Group 1a

192
Q

The Group II is the ______ response and the Group 1a is the _______ response.

A

Static

Dynamic

193
Q

What is the MOTOR innervation for the muscle spindle fibers?

A

gamma MN’s

They also set the sensitivity of the spindle

194
Q

The GTO is sensitive to…

A

Muscle Force (not stretch)

it is 1b afferent

195
Q

List the sensory nerve fiber classifications:

A

Ia (annulospiral ending from muscle spindle)
Ib (GTO)
II (flower spray on spindle)

A-beta (lower threshold cutaneous mechanoreceptors)
A-delta (aka group III) (nociceptors)
C (aka group IV) (nociceptors)

196
Q

Important things about dermatomes:

A

C7 marks leading edge of arm
L4-5 marks leading edge of leg
complete anesthesia requires 3 consecutive dorsal roots cut
C1/coccygeal have no dermatomes (no roots)

197
Q

What sensory modalities are carried by the Dorsal Column-Medial Lemniscal and the Trigeminal Lemniscal pathways?

A 
Discriminative touch
2-point touch
vibration
kinesthesis
stereognosis
198
Q

Where are the 1st, 2nd, and 3rd order neurons in the DCML?

A

1st - DRG A-betas run from peripheral to medulla
2nd - Medial Lemniscus (decussate as internal arcuate fibers, proceeds to thalamus)
3rd - VPL synapse, then thalamocortical projections proceed through corona radiata to cortex

199
Q

Where does DCML fiber enter the spinal cord, and what are they called once they ascend?

A

Medial regions of Lissauer’s tract

Fasciculus gracilis and Fasciculus cuneatus

200
Q

Where are the 1st, 2nd, and 3rd order neurons in the Trigeminal Lemniscal pathway?

A

1st - Trigeminal ganglion
2nd - Trigeminal sensory nucleus
3rd - VPM (thalamic)

201
Q

Where is the decussation of the trigeminal lemniscal pathway?

A

Pons

202
Q

Where do DCML fibers decussate?

A

Medulla

203
Q

The DCML lower extremity neurons synapse…

A

nucleus gracilis

204
Q

The DCML upper extremity neurons synapse…

A

nucleus cuneatus

205
Q

Where are the 1st, 2nd, and 3rd order neurons in the Spinothalamic tract?

A

1st - DRG
2nd - Substantia gelatinosa of Rexed’s lamina II
3rd - VPL (thalamus)

206
Q

Where does the decussation of the Spinothalamic tract occur?

A

within two levels of entrance into the spinal tract.

at the Anterior White Commisure

207
Q

Where are the 1st, 2nd, and 3rd order neurons in the Trigeminothalamic tract?

A

1st - Trigeminal ganglion
2nd - spinal nucleus in trigeminal n. in Medulla
3rd - VPM

208
Q

Where does the decussation of the Trigeminothalamic tract occur?

A

Medulla

209
Q

Both the spinothalamic and trigeminothalamic tracts carry what types of sensing fibers?

A

pain and thermal A-delta and C afferents

210
Q

Some fibers of what pathway terminate in the brainstem reticular formation and are called the spinoreticular tract fibers?

A

Lateral Spinothalamic tract

211
Q

The Lemniscal (DCML/trigeminal) and thalamic (lateral spinothalamic and trigeminothalamic) tracts are what type of pathways?

A

Conscious

212
Q

The DSCT and the SCCT relay what type of information?

A

Proprioception from spindles and tendon organs to the Cerebellum

213
Q

What are the 1st and 2nd order neurons in the Dorsal Spinocerebellar Tract?

A

1st - DRG
2nd - Clark’s column in nucleus dorsalis

No Cross

214
Q

What class of afferents are found in the DSCT?

A

Groups Ia and II (muscle spindle)

Ib (tendon organ)

215
Q

Where does the DSCT terminate, and what is its function?

A

Cerebellum via inferior cerebellar peduncle

Fine coordination posture and limb (LE)

216
Q

Where are the 1st and 2nd order neurons in the spinocuneocerebellar tract?

A

1st - DRG cervical
2nd - Cuneate nucleus

No decussation

217
Q

What is the nerve class in the Spinocuneocerebellar tract, where do the fibers enter the medulla, and what is their function?

A

Group Ia and II (muscle spindle) and Ib (tendon organ)
Inf. peduncle
fine coordination of UE mm.

218
Q

What type of info does the VSCT and the RSCT carry?

A

feedback to cerebellum about descending motor signals

219
Q

Where does the VSCT decussate?

A

Anterior white commisure

then, after entering the superior peduncle, MOST cross again and end up IPSILATERAL

220
Q

The RSCT (rostral spinocerebellar tract) carries what kind of info?

A

feedback to cerebellum about descending motor signals to cervical spinal cord.

221
Q

How many synapses are involved in the stretch reflex?

A

one

stretches Ia and Group II afferents and loops back to the homonymous muscle

222
Q

Does the stretch reflex involve the tendon organs?

A

NO

Tim's Cards (140 decks)

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