Exam #1: Sensory I Flashcards Preview

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Flashcards in Exam #1: Sensory I Deck (39):
1

Where is the dorsal column-- medial lemniscus (DC-ML)?

This is the white matter between the two "wings" of the gray matter butterfly

2

What does the DC-ML pathway relay?

- Discriminative (fine/detailed) touch
- Stereognosis
- Flutter- Vibratory sense
- General porprioception
- Light touch

3

What is stereognosis?

This is the ability to perceive and recognize the form of an object in the absence of visual and auditory information, by using tactile information to provide cues from texture, size, spatial properties, and temperature, etc

4

What is two-point discrimination testing? Inability with this test could indicate a problem with what anatomical structure?

This test determines the ability to distinguish between two stimuli; abnormality would indicate possible damage to the ML

5

Where is 2-point discrimination finest? Where is it the least discrimate?

- Fingertips
- Legs & back

6

What type of pathway is the DC-ML?

Ascending

7

How many neurons are in the DC-ML?

3

8

Where are the three cell bodies of the DC-ML?

1) DRG
2) NG or NC
3) VPL of Thalamus

9

What is the function of the FG?

Sensory information form the lower trunk & limb

10

What is the function of the FC?

Sensory information from the upper trunk & limb

11

What is the difference between the presence of FG & FC? Why?

- FC is only present from C1-T6
- FG is present throughout the entire cord

12

Where is the FC present in the spinal cord?

C1-T6

13

What is the last level where new fibers are added to the FG?

T7; the one superior are the ascending tracts from the levels below

14

What type of fibers does C1 have?

Motor ONLY; no sensory

15

Describe the morphology of ascending & descending tracts as they progress up/down the spinal cord.

Ascending tracts increase in diameter as they go upward

Descending tracts decrease in diameter as they go downward

16

List the receptor types that are involved in the DC-ML pathway.

Free nerve endings
Peritrichial nerve endings
Muscle spingle
GTO
Merkel's disc
Meissner's corpuscles
Pacinian corpuscles
Ruffini's end organs

17

Outline the DC-ML pathway.

Lower limb:
- Receptor
- FG
- Medulla- NG

Upper limb:
- Receptor
- FC
- NC

18

Where are first order cell bodies? What type of axons are sent to the second order neurons?

DRG

*A-alpha or beta i.e. heavily myelinated

19

Where are second order cell bodies?

Medulla--nuclei

20

Where do axons of the second order medullary nuclei go?

Arcuate
Medial Leminsicus

21

Where is the medial lemniscus?

Medulla

22

Where do axons of the ML go?

VPL of the Thalamus

23

Where do axons of the VPL of the Thalamus go?

Sensory cortex in the parietal lobe

24

Describe the organization of fibers in the FG & FC from medial to lateral.

SLTC

Medial to lateral=
- Sacral
- Lumbar
- Thoracic
- Cervical

25

What arteries supply blood to the dorsal column?

Posterior spinal arteries

26

What happens when there is a lesion in the spinal cord?

Damage of the ipsilateral dorsal column pathways at & below the level of the lesion

27

What happens when there is a lesion in the NG?

- Damage of the dorsal column pathways & their nuclei
- Deficits on the ipsilateral side

28

Where does crossing over occur?

After the NC/ NG

29

What happens if the lesion affects the ML itself? What artery supplies the ML?

Anterior spinal arteries

Note that there will be deficits on BOTH side of the body

30

A lesion above the sensory decussation will result in deficits on the _____ side of the body.

Contralateral

31

Where does the ML receive its blood supply in the rostral medulla? Occlusion will result in deficits on which side of the body?

Vertebral artery--opposite

32

Where does the ML receive its blood supply in the pons? Occlusion will result in deficits on which side of the body?

Basilar--opposite

33

Where does the ML receive its blood supply in the midbrain? Occlusion will result in deficits on which side of the body?

Posterior cerebral artery--opposite

34

What are the lenticulostriate arteries?

Deep branches of the MCA that supply the anterior & posterior limbs of the internal capsule

*****These arteries supply the 3rd order neurons of the DC-ML pathways in the VPL of the thalamus

35

What part of the DC-ML pathways does the anterior cerebral artery supply?

Somatosensory cortex:
- Leg & foot

36

What part of the DC-ML does the MCA supply?

Somatosensory cortex:
- Trunk
- Upper limb
- Face

37

What is the presentation of a lesion in the DC-ML?

- Sensory ataxia= "stamp & stick ataxia"
- Rhomberg's sign
- Tabes Dorsalis?

Grandpa

38

What is the dorsal spinocerebellar tract?

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39

What is the cuneocerebellar tract?

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