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Human Neuroscience > Lecture 11: Ascending Pathway II (ALS) > Flashcards

Lecture 11: Ascending Pathway II (ALS) Flashcards

1
Q

True or False: There is a fair amount of redundancy in the spinothalamic tract, spinoreticulothalamic tract, and spinotectal tract

A

True

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2
Q

True or False: The spinothalamic tract, the spinoreticulotract, and the spinotectal tract all contains a three neuron chain, similar to the DC-ML

A

True

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3
Q

Where is the primary and secondary neuron located in the ALS System?

A

Primary = cell body (DRG)
Secondary = substantia gelatinosa (lamina II) or lamina V of the dorsal horn of the spinal cord

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4
Q

Which three peripheral receptors are associated with the ALS?

A

Nociceptors
Thermoreceptors
Thermal Nociceptors

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5
Q

True or False: The peripheral axonal processes of the ALS start at the peripheral receptor and end in cell body of the DRG

A

True

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6
Q

In the ALS, nociceptors are associated with type 3 fibers (Agamma) and type IV (C) fibers. The prior are ____ axons for transmission of fast, sharp pain (first pain) whereas C are small ____ for transmission of slow, burning pain (second pain)

A. highly myelinated; unmyelinated
B. lightly myelinated; unmyelinated
C. non-myelinated; unmyelinated

A

B. lightly myelinated; unmyelinated

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7
Q

True or False: In the ALS, thermal receptors and thermal nociceptors are associated with Agamma and C fibers

A

True

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8
Q

In the ALS, the central axonal process starts at the cell body in the DRG and ends in the ___ of the spinal cord
A. Ventral Horn
B. Dorsal Horn

A

B. Dorsal Horn

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9
Q

The ALS central axonal processes enter the spinal cord through the _____ entry zone to enter ____ tract
A. medial dorsal entry zone; Lissauer’s tract
B. lateral dorsal entry zone; Lissauer’s tract

A

B. lateral dorsal entry zone; Lissauer’s tract

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10
Q

In the ALS system, there are collateral branches of the central processes that may ascend or descend in Lissauer’s tract and will terminal in the _____ to facilitate spinal reflexes

A

spinal gray matter

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11
Q

True or False: In the ALS, the main axon will enter the gray matter of the dorsal horn and synapse onto the third order neuron in the pathway

A

False - second order neuron

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12
Q

Which axons of the ALS will decussate in the anterior white commisure of the spinal cord and coalesce in the ____ as part of the ALS
A. spinal gray matter
B. spinal white matter

A

B. spinal white matter

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13
Q

True or False: The decussation of the second order neurons in the ALS does NOT take place at the level at which the information enters the spinal cord on the primary afferent, but it occurs over 1-2 spinal segments rostral to entry level

A

True

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14
Q

Which tract of the ALS is concerned with sharp, fast pain sensations?
A. STT
B. SRTT
C. SpTT

A

A. STT (spinothalamic tract)

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15
Q

True or False: The spinothalamic tract is somatotopically organized

A

True

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16
Q

In the STT, axons from the sacral cord are located ___ while those from the cervical cord are located ____
A. medially; laterally
B. laterally; medially

A

B. laterally; medially

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17
Q

The STT ascends in the ventrolateral aspect of the spinal ____ ____ over length of spinal cord
A. gray matter
B. white matter

A

B. white matter

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18
Q

In the medulla, the STT is located dorsolateral to the ____

In the pons, the STT is located lateral to the ___ ___

In the midbrain, the STT is located dorsolateral to the ___ ____
A. ML; ML; Superior Olivary Complex
B. Inferior Olivary Complex; ML; ML
C. ML; ML; Inferior Olivary Complex

A

B. Inferior Olivary Complex; ML; ML

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19
Q

The STT enters and terminates on neurons in the _______ - the third order neurons of this pathway
A. Medial Lemniscus
B. DRG
C. Spinal Gray Matter
D. Ventral Posterolateral Nucleus (VPL) of the Thalamus

A

D. Ventral Posterolateral Nucleus (VPL) of the Thalamus

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20
Q

True or False: The third order neuron of STT is located in the VPL nucleus of the thalamus

A

True

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21
Q

True or False: Fibers of the STT will synapse on neurons in the VPL

A

True

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22
Q

In the STT, axons of the VPL neurons project laterally out of the thalamus and course though the posterior limb of the ___ ___ to terminate in the _____ of the post central gyrus
A. ML; 1 Somatosensory Cortex
B. Internal capsule; Primary Somatosensory Cortex of the Post Central Gyrus

A

B. Internal capsule;
Primary Somatosensory Cortex of the Post Central Gyrus (Area 3, 1, and 2 Brodmann)

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23
Q

True or False: In the STT, the primary somatosensory cortex is located in the post-central gyrus of the parietal lobe; somatotopy is not preserved here and various body parts are equally represented in sensory homonculus

A

False - while in the STT, the primary somatosensory cortex is located in the post-central gyrus of the parietal lobe; somatotopy IS preserved here and various body parts are NOT equally represented in sensory homonculus

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24
Q

The second order fibers of the ALS course through the _____ to gain the contralateral side of the spinal cord.

Decussation occurs over distance of ___ spinal cord segments

A

anterior white commissure; 1-2

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25
Q

Which of the following tract of the ALS is concerned with slow, dull, aching pain and crude touch?
A. STT
B. SpTT
C. SRTT

A

C. SRTT

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26
Q

True or False: The spinothalamic tract is a indirect tract while the spinoreticulthalamic tract is considered to be a direct tract

A

False - STT = direct; SRT = indirect

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27
Q

Why do axons of the SRTT not end in the thalamus directly?

A

Leave tract as it courses through brain stem to synapse on neurons in the reticular formation

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28
Q

Where are the third order neurons of the SRTT located?
A. DRG
B. Thalamus
C. VPL of the Thalamus
D. Reticular formation of brainstem

A

D. Reticular formation (network of neurons in core of brainstem)

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29
Q

Where do third order neurons of the SRTT project their axons to?
A. Reticular Formation
B. VPN of the thalamus
C. Thalamus (intralaminar nuclei)

A

C. The thalamus (intralaminar nuclei of the thalamus)

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30
Q

What are the fourth order neurons for the SRTT known as?
A. Intralaminar Nuclei
B. Thalamic Neurons
C. DRG

A

B. Thalamic Neurons

31
Q

Where are thalamic neurons of the SRTT (aka the 4th order neurons) located?
A. DRG
B. VPL of thalamus
C. Intralaminar Nuclei

A

C. Intralaminar Nuclei

32
Q

True or False: The axons of the intralaminar thalamic nuclei neurons of the thalamic neurons (4th order) of the SRTT will project to widespread areas of the cerebral cortex, not just S-I

33
Q

Axons of the SpTT will ascend up the spinal cord and caudal brainstem in the ALS, but will leave tract via mid-brain to synapse on neurons in the ____ and ____
A. IC; PAG
B. SC; PAG
C. FG; FC

A

B. Superior Colliculus ; Peri-aquiductal Gray (PAG)

34
Q

Which neuron of the SpTT is involves in the reflex control of the head, neck, and eye movements towards noxious stimuli?
A. First order
B. Second order
C. Third order

A

C. Third order

35
Q

Which tract is associated with a descending tract to the upper cervical spinal cord?
A. Spinothalamic Tract
B. Spinoreticulothalamic Tract
C. Spinotectal Tract

36
Q

True or False: Third order neurons in the superior colliculus (SpTT) will contribute axons that form the Spinotectal Tract (SpTT)

37
Q

Which neurons of the spTT contribute to activation of polysynaptic, endogenous-opiate, descending pathway that will ultimately inhibit incoming pain afferent before they can activate spinothalamic and spinoreticulothalamic tracts?
A. Neurons of the PAG
B. Neurons in the superior colliculus

A

A. Neurons of the PAG

38
Q

In the SpTT, there are neurons in the PAG. Primary neurons ending in the substantia gelatinosa utilize ____ as a neurotransmitter

A

Substance P

39
Q

In the SpTT, ___ neurons in the substantia gelatinosa – a descending pathway from the PAG – will ultimately release ___ (which inhibit release of substance P) into the dorsal horn of the spinal cord
A. secondary; substance p
B. primary; enkephalins

A

B. primary; enkephalins

40
Q

True or False: The information carried in the SpTT reaches the level of consciousness

A

False - it does not

41
Q

What is the function of descending pathways, as seen in the spinotectal tract?

A

Control (feedback) from the sensory cortices and subcortical areas to the 1st and 2nd order neurons

42
Q

True or False: Ascending pathways modify activity of all descending systems - they are prominent in controlling conscious and reflex responses to noxious stimuli

A

False - DESCENDING pathways modify activity of all ASCENDING pathways - they are prominent in controlling conscious and reflex responses to noxious stimuli

43
Q

Which tract of the ALS is this?

46
Q

True or False: The ALS deals with pain, temp, and crude touch (tickle and itch)

47
Q

True or False: The Spinothalamic and Spinoreticulothalamic Tract reach consciousness while the Spinotectal Tract does NOT reach it

49
Q

True or False: In most cases, sensory neurons are found outside of the nervous system (in ganglions)

51
Q

All of the nociceptors and thermal receptors of the ALS belong to either ____ or ____ class

A

Aδ III or C (IV)

52
Q

Describe the conduction speed and myelination of Aδ III or C (IV)

53
Q

If you have a patient with a knife wound to the spinal cord that penetrates it from lateral to more medial, which sensations will the patient lose first? second
A. Pain; tactile
B. Tactile; pain

A

A. Pain; tactile

54
Q

The small fibers of the Dorsal Root Entry Zone enter, but stop at which location (aka first synapse is here)?
A. Lissauer’s Tract
B. Ventral Root
C. Interneurons
D. Substantia Gelatinosa

A

D. Substantia Gelatinosa

55
Q

Where do fibers of the secondary neuron decussate?

A

Anterior White Commisure

56
Q

Where does crossing over occur in the DC-ML?

57
Q

True or False: The second order fibers of the ALS course through the anterior white commisure to gain the contralateral side of the spinal cord

58
Q

For ___ axons of the ALX, decussation occurs over a distance of 1-2 spinal cord segments
A. 1-2
B. 2-3
C. 3-4

59
Q

If a patient is stabbed with a knife and it penetrates ALS, at T6. Will patient lose sensation ipsilaterally or contralaterally?

A

Contralaterally

60
Q

Cervical is more ___ while Sacral is more ___

A

lateral; medial

61
Q

Why do ALS fibers and DC-ML fibers contact different classes of relay neurons?

A

So nociceptive info remains segregated from mechanoreceptive info up to level of cortical circuits

62
Q

Which of the following is a a 4 neurons pathway?
A. STT
B. SRTT
C. Spinotectal Tract

63
Q

Is the stimulus the same for the STT and the SRTT?

64
Q

Where is the 2 neuron of the ALS always found?

A

Substantia gelatinosa!

  • sends info contralaterally
65
Q

What two structures make up the tectum?

A

Superior and Inferior Colliculi

66
Q

Which neuron is found in the SpTT Superior colliclus?
A. First order
B. Second oder
C. Third order

A

C. Third order

67
Q

In the SpTT, ALS activation of the PAG leads to polysynaptic pathway to ____ of spinal cord

In the SpTT, ALS activation of the Superior Colliculi leads to reflex pathway in the ____ of the cervical spinal cord

A

PAG = dorsal horn
SC = ventral horn

68
Q

In the ____, axons activate a multi-synaptic descending pathway that will
inhibit incoming pain afferents before they can activate the spinothalamic and
spinoreticulothalamic tracts
A. periaqueductal gray
B. superior colliculi
C. inferior colliculi

A

A. periaqueductal gray

69
Q

In the _____, the axons will form the tectospinal tract, a
descending tract to the upper cervical spinal cord (reflex control of
the head, neck and eye movement toward a noxious stimulus
A. periaqueductal gray
B. superior colliculi
C. inferior colliculi

A

B. superior colliculi

70
Q

The final neuron of the SpTT (descending pathway) releases enkephalin, which inhibits release of ____ and leads to STT and SRT switching off

A

substance P

71
Q

____ sensory neurons of the SpTT ending in the substantia gelatinosa use
Substance P

72
Q

The PAG receives inputs from hypothalamus via: ___ ____ ____
A. Ventral Longitudinal Fasciculus
B. Dorsal Longitudinal Fasciculus

A

B. Dorsal Longitudinal Fasciculus

Human Neuroscience (29 decks)

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