Lecture 7: Sensory Systems 2 Flashcards

1
Q

Which type of fiber has the fastest conduction speed in spinothalamic pathways

A

A aloha fibers

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2
Q

Which type of fiber has the slowest conduction speed in spinothalamic pathways

A

C fibers

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3
Q

Why are C fibers slower than alpha fibers

A

Not myelinated

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4
Q

In spinothalamic pathways, what are a alpha fibers responsible for (sensation)

A

Proprioception

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5
Q

In spinothalamic pathways, what a beta fibers responsible for (sensation)

A

Tough (ex: fine touch, vibration, pressure)

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6
Q

In spinothalamic pathways, what are a delta fibers responsible for (sensation)

A

Temperature and sharp pain

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7
Q

True of false: a delta fibers are responsible for temperature and dull pain

A

False, sharp pain

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8
Q

In spinothalamic pathways, what C fibers fibers responsible for (sensation)

A

Dull pain, temp and itch

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9
Q

Dull pain, temp and itch is associated with what fibers in the spinothalamic pathways

A

C fibers

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10
Q

Temp and sharp pain is associated with what fibers in the spinothalamic pathways

A

A delta

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11
Q

Touch is associated with what fibers in the spinothalamic pathways

A

A beta

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12
Q

Proprioception is associated with what fibers in the spinothalamic pathways

A

A alpha

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13
Q

True or false, a delta fibers are faster than a alpha

A

False, they are smaller d slower

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14
Q

Put these in order from slowest to fastest
A alpha
C fibers
A delta
A beta

A

C fibers
A delta
A beta
A alpha

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15
Q

The anterolateral system is made up of what 2 pathways

A

Lateral spinothalamic
Anterior spinothalamic

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16
Q

What type of sensation does the lateral spinothalamic pathway caddy

A

Pain and temperature sensation

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17
Q

What type of sensation does the anterior spinothalamic pathway caddy

A

Crude touch and pressure sensation

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18
Q

True or false and why: Crude touch and pressure sensation are associated with the lateral spinothalamic pathways

A

False, with anterior

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19
Q

What are the 3 features of typical sensory pathways (3 neuron rule)

A

Primary (1o; first order) neuron: cell bodies in dorsal root ganglia
• Secondary (2o; second order) neuron: axons decussate
• Tertiary (3o; third order) neuron: cell bodies in thalamic nuclei

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20
Q

1st order neutrons synapse where with 2nd order neutrons (general)

A

In brain stem nucleus (NG OR NCH) OR dorsal horn

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21
Q

2nd order neutrons synapse where with 3rd order neutrons (general)

A

Thalamus (Vpl or Vpm)

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22
Q

2nd order neutrons synapse where with 3rd order neutrons (general)

A

Primary somatosensory cortex

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23
Q

In the spinothalamic pathways were do primary sensory neutrons enter

A

The socks enter via the dorsal horn

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24
Q

True or false: like in the DCML pathway, in the spinothalamic pathway, the primary sensory neutrons do not synapse in the dorsal horn

A

False, in the spinothalamic they do

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25
Q

In the ST TRACT , what happens when primary sensory neutrons axons enter the dorsal horn

A

They Ascend (or descend) 1–2 spinal segments via posterolateral / dorsolateral (Lissauer’s) tract (black
arrow) à for the

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26
Q

In the ST tract, the primary sensory neutrons They Ascend (or descend) 1–2 spinal segments via what tract

A

posterolateral / dorsolateral (Lissauer’s) tract

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27
Q

in the ST tract, where do the primary neurons synapse with the secondary neurons

A

in the nucleus proprius of dorsal horn

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28
Q

where is the in the nucleus proprius located

A

in the dorsal horn

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29
Q

cells in nucleus proprius have processes that extend into what part

A

substantia gelatinosa

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30
Q

cells in nucleus proprius have processes that extend into substantia gelatinosa which is important for what modality

A

pain modulation

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31
Q

true or false, there is decussation in the ST tract at the level of the 1st neuron synapsing with the seconding

A

true

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32
Q

how do the secondary neurons of the ST trat decussatie

A

via the anterior white commissure and ascend contralateral spinothalamic tracts

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33
Q

true or false: neurons in the ST tract decussate via the posterior white commissure and ascend contralateral spinothalamic tracts

A

false, via the anterioe white comisure

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34
Q

explain the somatotropic organization of the spinothalamic tracs

A

2nd sensory neuron axons from lumbosacral = superficial and lateral

cervical areas=deep medial

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35
Q

where is the spinal leminscus located in relation tothe rostral medulla

A

dorsal to inferior olivary nuclei and ventral to the inferior cerebellar peduncles

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36
Q

where is the spinal leminscus located in relation tothe pons

A

along the lateral edge of pontine tegmentum (dorsal to medial lem)

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37
Q

where is the spinal leminscus located in relation tothe midbrain

A

just dorsal to the medial leminsucs

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38
Q

in the ST tract, after entering the brainstem, the travts formed by secondary sensory neuron axons in the spinothalmic patjways are called what

A

spinal leminscus

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39
Q

when are the tracts formed by secondary sensory neuron axons in the spinothalmic patjways called spinal leminscus

A

after entering the brain stem

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40
Q

in the ST tract, where do the sensory neurons synapse with tertiary sesory neurons

A

in the thalamus (posterior ventral thalamic nuclei)

VPL=body, axial and appendicular
VPM = face (via trigem)

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41
Q

in the ST tract, axons of the tertiary neurons travel through where

A

internal capsule (posterior limb) and corona radiata before terminating in primary somatosensory cortex

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42
Q

what type of fibers make up the corona radiata

A

thalamocortical fibers

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43
Q

what is the general process of the spinothalamic pathways

A

1) primary sensory neuron enters dorsal horn (cell body in dorsalroot gangilon)
=ascends (or descends) 1-2 segments in posterolatral (lissauers tract)

2) synapse with 2 sensory neuron in dorsal horn (nucleus proprious which communicates with substantia gelatinosa)

3) decussation occurs thru anterior white commissure

4) goes up as spinothalamic tract (anterior or lateral = depending on modality)

5) spinal leminstem (in brainstem)

6) synapse with 3 sensory neuron (in VPL of thalamus)

7) interna; capsule (post limb)

8) corona radiata

9) primary sensory cortex (post central gyrus)

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44
Q

What minor pathway brings visceral responses to nociceptibe stimuli

A

Spinohypothalamic

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45
Q

true or false: spinocerebellar pathways are responsble for non concious sensory pathways

A

true

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46
Q

how many neurons are involved in the spinocerebellar pathways

A

only 2 neurons

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47
Q

spinocerebellar pathways carry non concious propriception where

A

to ipsilateral cerebellum

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48
Q

where do spinocerebellar pathways get their info

A

from proprioceptors (msucles, tendons,joints) and exteroceptors (cutanrous receptors)

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49
Q

lesions in spinocereballr pathways lead to what

A

ataxia (loss of muscle coordination)

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50
Q

true or false: spinocerebellar pathways are often damagaed in isolation

A

false, rarely damaged in isolation from other concious pathways

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51
Q

what are spinal border cells

A

collection of cell bpdies on dorsolateral aspect of ventral horn (lumbar and cervical regions)

52
Q

what is nucleus dorsalis

A

column of stacked nuclei between c8-l2

53
Q
A
54
Q

How many cerebellar pathways are they

A

4

55
Q

What type of fibers (general characteristics) would have the fastest conduction speed

A

Bigger and myelinated

56
Q

What are some examples of a alpha fibers

A

Golgi tendons
Muscle spindles
Joint receptors

57
Q

Why do fibers associated with proprioception need to have fast conduction speed

A

Need to be able to alter and change body position quickly

58
Q

Which fibers are important in the DCML

A

A beta

59
Q

If you have an initial prick and then a throb, which fibers are associated

A

A delta (initial prick)
C fibers (dull pain)

60
Q

What are the two pathways associated with the anterolateral system

A

Lateral and anterior spinothalamic pathways

61
Q

Pin prick test tests which pathways

A

Lateral spinothalamic pathways

62
Q

What are the 3 key differences between the DCL and spinothalamic

A

Carries different types of sensory modalities
Location of synapse between primary and secondary (in the brain stem vs the dorsal horn)
Diff location of decussation

63
Q

free question… good job :) <3

A

:)

64
Q

Is the dorsolatefal tract white or grey matter

A

White

65
Q

What two structures in the dorsal horn communicate for pain modulation

A

Nucleus propeius and substantia gelatinosa

66
Q

In the rostral medulla, is the spinothalamic tract located medially or lateral

A

Lateral

67
Q

True or false: the DCML tract and spinothalamic tract have the same blood supply

A

False, different

68
Q

What is the tract called before it is called spinal lemniscus

A

Spinothalamic tract

69
Q

In the midbrain, does the spinal lemniscus get closer or further from medial leminscus

A

Closer

70
Q

What is the function of the spinohypothalamic pathways

A

Direct visceral responses to nociceptibe stim

71
Q

What minor pathway is responsible for reflexive head and eye movements in response to stim and pain modulation via periaqueductall grey

A

Spinomesencephalic/spinotectal

72
Q

What is the function of spinomesencephalic
Pathways

A

responsible for reflexive head and eye movements in response to stim and pain modulation via periaqueductall grey

73
Q

Where does the spinomesencephalic pathway go

A

Midbrain (and sup colliculi)

74
Q

What is the function of the spinoreticular pathway

A

Automatic responses to nociceptive stimuli
(e.g., increase in awareness / arousal) & pain modulation via reticular nuclei

75
Q

Where does the spinoreticular pathway send info to

A

Reticular formation

76
Q

Automatic responses to nociceptive stimuli
(e.g., increase in awareness / arousal) & pain modulation via reticular nuclei

Is what pathway

A

Spinoreticular

77
Q

Spinocerebellr pathqays carry non conscious or conciosi proprioception

A
78
Q

What are the 3 ways that we get info from the brain stem to cerebellum in spinocerebellar pathways

A

Superior middle and inferior cerebellar peduncle

79
Q

Superior cerebellar peduncle is associated with what spinal structure

A

Midbrain

80
Q

Middle cerebellar peduncle is associated with what spinal structure

A

Pons

81
Q

Inferior cerebellar peduncle is associated with what spinal structure

A

Medulla

82
Q

What are the 4 spinocerebellar pathways

A

Dorsal
Ventral
Rostral
Cuneo

83
Q

Explain the dorsal spinocerebellar pathway

A

1o neuron enters dorsal horn

• Synapses with 2o neuron in nucleus dorsalis* à
these nuclei are present from C8–L2 / L3

• Fibers below L2 / L3 will ascend in ipsilateral fasciculus gracilis

• 2o neuron ascends in ipsilateral dorsal spinocerebellar tract

• Enters cerebellum via inferior cerebellar peduncle
(connects medulla oblongata to cerebellum)

• Information from lower limbs

*Nuclei dorsales (plural of nucleus dorsalis) have widespread connectivity & integrate information about the entire lower limb à filter and streamline information being sent to cerebellum; responsible for proprioceptive processing, motor planning, & evaluation
14

84
Q

In the DSCP, where do primary neutrons enter

A

Dorsal horn

85
Q

Where do all primary neutrons in the spinocerebellad pathway enter

A

Thru dorsal horn

86
Q

Which of the 4 spinocerebellar pathways ascend right after entering the dorsal horn

A

Cuneo cerebellar

87
Q

Where does the primary neuron synapse with secondary in the DSCP

A

in nucleus dorsalis (present from c8-l2,l3)

88
Q

In the DSCP, fibers below BLANK must ascend in ipsilateral fasciculus gracilis

A

L2 L3

89
Q

Explain why in the DSCP, L1L2 must ascend in ipsilateral fasciculus gracilis before synapsing

A

Because the nucleui dorsali end at l2l3

90
Q

Where does the secondary neuron ascend in the DSCP

A

ascend in ipsilateral dorsal spinocerebellar tract

91
Q

How does info from DSCP enter cerebellum

A

Via inferior cerebellar peduncle
(connects medulla oblongata to cerebellum)

92
Q

The DSCP Carries info from what part of the body

A

Lower limbs

93
Q

*Nuclei dorsales (plural of nucleus dorsalis) have widespread connectivity & integrate information about the entire upper or lower limb

A

Lower limb

94
Q

What is the function of nucleus dorsales

A

filter and streamline information being sent to cerebellum; responsible for proprioceptive processing, motor planning, & evaluation

95
Q

True or false: in the DSCP pathway, fibers from below l2l3 must ascend in contralateral fasciculus gracilis

A

False, ipsilateral

96
Q

Does the DSCP PATHWAY deccusatw

A

No

97
Q

Where does the primary neuron enter in the cuneocerebellar pathway

A

The dorsal column

98
Q

True or false and explain, in the Cuneo pathways, the ascends right away

A

True it enters dorsal horn and ascends in ipsilateral fasciculus cuneatusàjust like in the DCML pathway

99
Q

Where do the primary neutrons synapse with the secondary neutrons in the Cuneo pathway

A

In accessory nucleus cuneatus in medulla oblongata

100
Q

How does info from the Cuneo pathway enter the cerebellum

A

Enters cerebellum via inferior cerebellar peduncle (connects medulla oblongata to cerebellum)

101
Q

True or false: both the Cuneo and DSCP pathways enter cerebellum via inferior cerebellar peduncle

A

True

102
Q

Which pathway is equivalent to the DSCP but for upper limbs

A

Cuneo

103
Q

What structure is functionally analogous to nucleus dorsales by integrating info about the entire upper limb

A

Accessory nucleus cunnearus

104
Q

what is the only spinocerebllar pathways that decussates

A

Ventral spino

105
Q

Explain the cuneocerebellar (general)

A

1o neuron enters dorsal horn and ascends in ipsilateral fasciculus cuneatusàjust like in the DCML pathway

• Synapses with 2o neuron in accessory nucleus cuneatus* in medulla oblongata

• Enters cerebellum via inferior cerebellar peduncle (connects medulla oblongata to cerebellum)

• Equivalent to dorsal spinocerebellar pathway, but for upper limbs
*Accessory nucleus cuneatus is functionally analogous to the nuclei dorsales, integrating information about the entire upper limb
15

106
Q

Explain the ventral spinocerebellar pathwy

A

1o neuron enters dorsal horn

• Synapses with 2o neuron in lumbar spinal border
cellsàdorsolateral aspect of anterior horn

• 2o neuron decussates in anterior white commissure and ascends in contralateral ventral spinocerebellar tract

• Enters cerebellum via superior cerebellar peduncle (connects midbrain to cerebellum)

• 2o neuron decussates a second time in the white matter of the cerebellum to end up on ipsilateral side (with respect to the 1o neuron)
• Information from lower limbs

107
Q

What two spinocerebellar pathways carry info from lower limbs

A

Dorsal spinocereblar
Ventralspimocerebllar

108
Q

What two spinocerebellar pathways carry info from upper limb

A

Cuneocerebellar
Rostralspinocerebellar

109
Q

where does the primary neuron enter for the VSCP

A

Dorsal horn

110
Q

Where does the primary neuronvsynapse with the secondary neuron in the VSCP

A

In lumbar spinal border cells
(Dorsolateral aspdct of anterior horn)

111
Q

How does info from the VSCP enter cerebellum

A

Superior cerebellar peduncle

112
Q

What two pathways use the superior cerebellar peduncle to enter the cerebellum

A

Ventral spinocerebllar
Rostral spinocerebellar

113
Q

True or false: only spinocerebellar pathway fhatcdecussates is the RSCP

A

False
The VSCP

114
Q

where does the secondary neuron decussate first in the VSCP

A

anterior white commissure and ascends in contralateral ventral spinocerebellar tract

115
Q

After the secondary neuron decussates for the first time in the VSCP, how does it ascend

A

Via contralateral ventral spinocerebllar tract

116
Q

where does the secondary neuron decussate second in the VSCP

A

2o neuron decussates a second time in the white matter of the cerebellum to end up on ipsilateral side (with respect to the 1o neuron)

117
Q

True or false and explain
Because the VSCP pathway decussates in the anterior commissure, it is a contralateral system

A

False, it decussates a second time so it ends up on ipsilateral side

118
Q

Does the VSCP carry info from upper or lower limb

A

Lower limb

119
Q

Explain the rostral spinocerebllar pathway

A

• 1o neuron enters dorsal horn

• Synapses with 2o neuron in cervical spinal border
cellsàdorsolateral aspect of anterior horn

• 2o neuron ascends in ipsilateral rostral
spinocerebellar tract

• Enters cerebellum via superior cerebellar peduncle (connects midbrain to cerebellum)

• Equivalent to ventral spinocerebellar pathway, but for upper limbs

120
Q

In the RSCP, where does the primary neuron enter

A

Via the dorsal horn

121
Q

Where does the primary neuron synapse with the secondary neuron in the RSCP PATHW

A

in cervical spinal border cells

122
Q

where do secondary neutrons ascend in RSCP

A

in ipsilateral rostral spinocerebellar rract

123
Q

How does info from RSCP enter cerebellum

A

Via superior cerebellar peduncle (connects midbrain to cerebellum)

124
Q

The rostral is equivalent to what other pathway but for the upper limbs

A

Ventral

125
Q

What are the major differences between rostral and ventral spinocerebllar pathways

A

1) location of secondary synapse (ventral = lumbar spinal border cells since from lower limb, rostral = cervical spinal border cells since upper limb)

2) ventral pathways decussates twice (rostral does not decussate)

3) ventral, Carrie’s info from lower limb while rostral Carrie’s from upper limb

126
Q

What are the major differences between the dorsal and Cuneo cerebellar pathways

A

Location of synapse with secondary neuron (dorsal= nucleus dorasalis , Cuneo=accessory nucleus cunearus)

Upper vs lower limbs