Exam #2: Lab Flashcards Preview

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Flashcards in Exam #2: Lab Deck (77):
1

What sensations are conveyed by the DC/ML pathway?

Proprioception
Discriminative touch
Vibratory sense

2

What sensations are conveyed by the Spinothalamic Tract?

Pain
Temperature
Crude Touch

3

What is Lissaruer’s Tract?

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

4

What is the substantia gelatinosa?

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

5

Where does the spinothalamic tract cross over?

Anterior white commissure

6

What is the fasiculus gracilis?

This is part of the DC/ML pathway thats transmits:
- Proprioception
- Fine discriminating touch

*****From T6 down

7

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

- Lateral column of the spinal cord
- PNS cell bodies located at S2, 3, & 4 that are PRE-GANGLIONIC cell bodies

8

What happens above T6 in the dorsal faniculi?

The fasiculus cuneatus emerges lateral to the fasiculus gracilis

9

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

SNS—pre-ganglionic

10

Which is medial, Fasiculus Gracilis or Cuneatus?

Fasiculus Gracilis—always next to the dorsal median sulcus

11

What separates the Fasiculus Cuneatus & Gracilis?

Dorsal/ posterior intermediate sulcus

12

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

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

13

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

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.

14

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

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

15

What is the Gracile Tubercle?

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

16

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

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

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

17

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

Gracile Nucleus

18

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

Cuneate Nucleus

19

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

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

****Has NOT crossed over yet

20

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

Internal arcuate fibers

21

Where are the internal arcuate fibers synapsing?

Gracile Nucleus & Cuneate Nucleus to the Medial Lemniscus

22

How is the ML organized?

Somatotopically

23

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

“Drunken sailor that is still standing upright”

Neck
Hand
Chest
Arm
Leg
Foot

24

What is the landmark for the rostral medualla?

Open 4th ventricle

25

What does the inferior cerebellar peduncle connect?

Cerebellum to the medulla & spinal cord

26

What is the landmark for the caudal pons?

Closed 4th ventricle
Basilar pons (transverse fibers)

27

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

Tegmentum

28

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

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

29

What is the landmark for the rostral pons?

Cerebellar hemispheres come into view

30

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

These previously distinct pathways merge in the tegmentum

31

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

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

32

What are the landmarks for the caudal midbrain?

- Cerebral aqueduct & the periaqueductal grey
- Decussation of the SCP

33

What is the periaqueductal grey associated with?

Pain transmission

34

What happens to the ML in the caudal midbrain?

Inverted somatotopic arrangement as the pathways has been pushed laterally

****I.e. "drunken sailer" is now upside-down

35

What are the landmarks for the rostral midbrain?

Red Nucleus

36

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

Completely inverted with the feet region laterally & neck medially

37

What is the landmark for the two geniculate nuclei?

Thalamus

38

What are the crus cerebri?

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

39

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

VPL

40

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

Posterior limb of the internal capsule

41

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

VPL

42

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

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

43

What is the alternate name for the corticospinal tract?

Pyramidal Tract

44

What is the alternate name for the corticonuclear tract?

Bulbar Tract

45

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

Pre-central gyrus of the cerebral cortex

46

What is the lateral corticospinal tract?

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

47

What is the anterior corticospinal tract?

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

48

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

UMN

49

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

LMNs in the anterior horn of the grey matter

50

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

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

51

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

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

52

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

MCA- CONTRAlateral side of the body

53

What blood vessel supplies the medial surface of the cortex?

Anterior cerebral artery – CONTRAlateral side of the body

54

What are the parts of the internal capsule?

Anterior limb
Genu
Posterior limb

55

Where is the anterior limb of the internal capsule located?

Between the caudate nucleus & globus pallidus

56

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

Descending fibers of the corticonuclear tract associated with the head

57

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

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

58

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

Thalamus

59

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

Crus cerebri & pons

60

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

Cerebral aqueduct
Red nucleus
Superior colliculus
Crus cerebri

61

What is the epithalamus part of?

Diencephalon

62

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

Corticonuclear tract

63

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

Crus Cerebri
Decussation of the SCP
Rostral pons

64

What is the major hallmark of the rostal midbrain?

Red Nucleus

65

What are the hallmarks of the rostral pons?

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

66

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

These tracts blend

67

What is the hallmark of the caudal pons?

Closed 4th ventricle
Basal pons

68

What is the hallmark of the rostral medulla?

Open 4th ventricle
Infra-olivary nucleus

69

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

Pyramids

70

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

Infra-olivary nucleus WITHOUT 4th ventricle

71

Where do the corticonuclear tracts disappear from the brain?

Caudal medulla

72

Where does the decussation of the corticospinal tracts occur?

Caudal medulla

73

Describe the morphology of the decussation of the corticospinal tract.

Heart in caudal medulla

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

74

Which distal section of the corticospinal tract DOES NOT decussate?

Anterior corticospinal tract

75

Which distal section of the corticospinal tract DOES decussate?

Lateral corticospinal tract

76

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

LMN cell bodies

77

Where does the anterior corticospinal tract decussate?

Anterior white commissure at the specific level the nerve innervates