Exam #2: Lab Flashcards

1
Q

What sensations are conveyed by the DC/ML pathway?

A

Proprioception
Discriminative touch
Vibratory sense

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2
Q

What sensations are conveyed by the Spinothalamic Tract?

A

Pain
Temperature
Crude Touch

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3
Q

What is Lissaruer’s Tract?

A

White matter tract just above the dorsal horn of the grey matter—these are myelianted axons from cell bodies in the first order neurons of the ascending Spinothalamic/ Anterolateral tract that carry:

  • pain
  • temp
  • crude touch
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4
Q

What is the substantia gelatinosa?

A

2nd order neurons of the Spinothalamic Tract (from Lissauer’s Tract—ascend or descend 1st) that carry:

  • pain
  • temp
  • crude touch
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5
Q

Where does the spinothalamic tract cross over?

A

Anterior white commissure

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6
Q

What is the fasiculus gracilis?

A

This is part of the DC/ML pathway thats transmits:

  • Proprioception
  • Fine discriminating touch

*****From T6 down

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7
Q

What is the intermediolateral cell column in the sacral spinal cord?

A
  • Lateral column of the spinal cord

- PNS cell bodies located at S2, 3, & 4 that are PRE-GANGLIONIC cell bodies

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8
Q

What happens above T6 in the dorsal faniculi?

A

The fasiculus cuneatus emerges lateral to the fasiculus gracilis

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9
Q

At T4, what cell bodies are present in the interolateral cell column?

A

SNS—pre-ganglionic

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10
Q

Which is medial, Fasiculus Gracilis or Cuneatus?

A

Fasiculus Gracilis—always next to the dorsal median sulcus

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11
Q

What separates the Fasiculus Cuneatus & Gracilis?

A

Dorsal/ posterior intermediate sulcus

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12
Q

What is the Dorsal Nucleus of Clarke or Clarke’s Nucleus?

A

Nucleus in the thoracic cord that transmits proprioceptive fibers from the spinal cord to the cerebellum

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13
Q

In reference to the spinothalamic tract, what happens in the upper cervical spinal cord i.e. C1-C5?

A

This is the location of the junction between Lissauer’s Tract & CN V

  • pain
  • temp
  • crude touch

*****All still being carried by these fibers; however, now they’re being carried by the cranial nerve.

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14
Q

What happens to the substania gelatinosa in the upper cervical region?

A

This is now the “Spinal Nucleus of CN V” or the “Gelatinosa” portion of CN V

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15
Q

What is the Gracile Tubercle?

A

Posterior swelling in the medulla that is the anatomic landmark for nucleus gracilis

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16
Q

What is the Cuneate Tubercle? Where is it relative to the Gracile Tubercle?

A

This is the anatomic landmark for the cuneate nucleus in the medulla

*****It is superior & lateral to the Gracile Tubercle

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17
Q

In the caudal medulla cross-section, what is the clearer staining region in the Fasciculus Gracilis?

A

Gracile Nucleus

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18
Q

In the caudal medulla cross-section, what is the clearer staining region inferior to the Fasiculus Cuneatus?

A

Cuneate Nucleus

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19
Q

What order neurons are in the Gracile Nucleus & Cuneate Nucleus?

A

These are the 2nd order neurons of the DC/ML pathway (proprioception & discriminative touch)

**Has NOT crossed over yet

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20
Q

What are the fibers that cross-over in the DC/ML pathway?

A

Internal arcuate fibers

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21
Q

Where are the internal arcuate fibers synapsing?

A

Gracile Nucleus & Cuneate Nucleus to the Medial Lemniscus

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22
Q

How is the ML organized?

A

Somatotopically

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23
Q

Outline the somatotopic organization of the ML in the medulla at the level of the sensory decussation.

A

“Drunken sailor that is still standing upright”

Neck 
Hand 
Chest 
Arm 
Leg 
Foot
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24
Q

What is the landmark for the rostral medualla?

A

Open 4th ventricle

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25
Q

What does the inferior cerebellar peduncle connect?

A

Cerebellum to the medulla & spinal cord

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26
Q

What is the landmark for the caudal pons?

A
Closed 4th ventricle 
Basilar pons (transverse fibers)
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27
Q

In the caudal pons, what region are the spinothalamic & DC/ML pathways in?

A

Tegmentum

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28
Q

How does somatotopic arrangement of the ML change in the caudal pons?

A

“Drunken sailor” gets a bit drunker & slouches i.e. becomes more horizontal

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29
Q

What is the landmark for the rostral pons?

A

Cerebellar hemispheres come into view

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30
Q

What happens to the ML & spinothalamic pathways in the rostral pons?

A

These previously distinct pathways merge in the tegmentum

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31
Q

How does somatotopic arrangement of the ML change in the rostral pons?

A

“Drunken sailor” has passed out & is now completely horizontal w/ feet lateral

32
Q

What are the landmarks for the caudal midbrain?

A
  • Cerebral aqueduct & the periaqueductal grey

- Decussation of the SCP

33
Q

What is the periaqueductal grey associated with?

A

Pain transmission

34
Q

What happens to the ML in the caudal midbrain?

A

Inverted somatotopic arrangement as the pathways has been pushed laterally

**I.e. “drunken sailer” is now upside-down

35
Q

What are the landmarks for the rostral midbrain?

A

Red Nucleus

36
Q

How has the somatotopic arrangement of the ML changed in the rostral midbrain?

A

Completely inverted with the feet region laterally & neck medially

37
Q

What is the landmark for the two geniculate nuclei?

A

Thalamus

38
Q

What are the crus cerebri?

A

White matter tracts coming down from the cerebral cortex into the pons

39
Q

What nucleus of the thalamus are the spinothalamic & DC/ML pathways synapsing with?

A

VPL

40
Q

Where are the axons of the VPL nucleus of the thalamus synapsing?

A

Posterior limb of the internal capsule

41
Q

What are the third order neurons of the spinothalamic & DC/ML pathways?

A

VPL

42
Q

Where are the axons of the VPL nucleus of the thalamus going?

A

Post-central gyrus of the cerebral cortex i.e. the somatosenory cortex

43
Q

What is the alternate name for the corticospinal tract?

A

Pyramidal Tract

44
Q

What is the alternate name for the corticonuclear tract?

A

Bulbar Tract

45
Q

Where are the cell bodies of the neurons composing the corticospinal & corticonuclear tracts located?

A

Pre-central gyrus of the cerebral cortex

46
Q

What is the lateral corticospinal tract?

A

UMNs of the corticospinal tract that have descended from the pre-central gyrus & crosse-over to the lateral faniculus

47
Q

What is the anterior corticospinal tract?

A

UMNs of the corticospinal tract that have descended from the pre-central gyrus & NOT crossed-over, they remain midline & form the anterior faniculus

48
Q

What type of neurons are the neurons of the lateral & anterior corticopsinal tracts?

A

UMN

49
Q

What neurons do the anterior & lateral corticospinal tract synapse with?

A

LMNs in the anterior horn of the grey matter

50
Q

Where in the pre-central gyrus does the corticonuclear originate?

A

Facial region (near the lateral sulcus) of the somatotopic arrangement

51
Q

Where in the pre-central gyrus does the corticospinal tract originate?

A

Upper arm & trunk region (medial portion of the lateral aspect) in the somatotopic arrangement of the pre-central gyrus

52
Q

What blood vessel supply the lateral surface of the cortex/ pre-central? What area of the body will be affected?

A

MCA- CONTRAlateral side of the body

53
Q

What blood vessel supplies the medial surface of the cortex?

A

Anterior cerebral artery – CONTRAlateral side of the body

54
Q

What are the parts of the internal capsule?

A

Anterior limb
Genu
Posterior limb

55
Q

Where is the anterior limb of the internal capsule located?

A

Between the caudate nucleus & globus pallidus

56
Q

What fibers are associated with the genu of the internal capsule?

A

Descending fibers of the corticonuclear tract associated with the head

57
Q

What fibers are associated with the posterior limb of the internal capsule?

A

Descending fibers of the corticospinal tract i.e. fibers associated with the UE, trunk, & leg

58
Q

What is the landmark for the posterior limb of the internal capsule on coronal section?

A

Thalamus

59
Q

What does the posterior limb of the internal capsule continue into?

A

Crus cerebri & pons

60
Q

What are the hallmark’s of the rostral midbrain? Name four.

A

Cerebral aqueduct
Red nucleus
Superior colliculus
Crus cerebri

61
Q

What is the epithalamus part of?

A

Diencephalon

62
Q

What is medial in the crus cerebri, the corticospinal or corticonuclear tract?

A

Corticonuclear tract

63
Q

What are the hallmarks of the caudal midbrain? Name three.

A

Crus Cerebri
Decussation of the SCP
Rostral pons

64
Q

What is the major hallmark of the rostal midbrain?

A

Red Nucleus

65
Q

What are the hallmarks of the rostral pons?

A
Cerebellar hemispheres 
Open 4th ventricle 
SCP & MCP 
Tegmentum 
Basilar Pons
66
Q

What happens to the corticospinal & corticonuclear tracts in the rostral pons?

A

These tracts blend

67
Q

What is the hallmark of the caudal pons?

A

Closed 4th ventricle

Basal pons

68
Q

What is the hallmark of the rostral medulla?

A

Open 4th ventricle

Infra-olivary nucleus

69
Q

What do the corticospinal & corticonuclear tracts merge to form in the rostral medualla?

A

Pyramids

70
Q

How do you know that you’re in the caudal medulla on cross-section?

A

Infra-olivary nucleus WITHOUT 4th ventricle

71
Q

Where do the corticonuclear tracts disappear from the brain?

A

Caudal medulla

72
Q

Where does the decussation of the corticospinal tracts occur?

A

Caudal medulla

73
Q

Describe the morphology of the decussation of the corticospinal tract.

A

Heart in caudal medulla

**Note that ~85% decussate; 15% does NOT

74
Q

Which distal section of the corticospinal tract DOES NOT decussate?

A

Anterior corticospinal tract

75
Q

Which distal section of the corticospinal tract DOES decussate?

A

Lateral corticospinal tract

76
Q

What is located in the anterior horn of the spinal cord?

A

LMN cell bodies

77
Q

Where does the anterior corticospinal tract decussate?

A

Anterior white commissure at the specific level the nerve innervates