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Flashcards in Ascending and Descending tracts Deck (35):
1

What modality are ascending tracts

Sensory

2

What modality are descending tracts

Motor

3

What is the DCML

Dorsal Column Medial Lemniscus tract

4

What sensation does the DCML detect

fine touch
conscious proprioception

5

Where do fibres in the DCML tract cross over to the contralateral side

2nd order nerves cross over at the level of the medulla

6

What is the dorsal column in the spinal cord made up of

fasiculus gracilis
fasiculus cuneatus

7

From where does the nucleus gracilis carry information

Legs

8

From where does the nucleus cuneatus carry information

arms

9

What is the STT

Spinothalamic tract

10

What sensation does the STT detect

pain
temperature
crude touch / deep pressure

11

Where do fibres in the STT cross over to the contralateral side

2nd order neurons cross over segmentally at the level they enter the spinal cord

12

What action does the corticospinal tract help control

fine motor movement

13

What is the corticospinal tract also known as (CST)

pyramidal tract

14

what kinds of corticospinal tracts are there

lateral and ventral

15

_% fibres cross over __ in the lateral CST

85% fibres cross over the midline at the decussation of the pyramids in the medulla

16

where do fibres in the ventral CST cross over

segmentally in the spinal cord as they need to leave

17

What is the internal capsule

deep subcortical tissue of white matter, all modalities run through this

18

Give examples of extra-pyramidal tracts

tectospinal - input to H+N region
reticulospinal - reticular formation at core of brainstem (pons and medulla): consciousness, breathing, cariac
vesticulospinal - input to anti-gravity muscles

19

What is Brown Séquard syndrome

hemisection of the spinal cord resulting in:
ipsilateral loss of fine touch, proprioception and fine movement (DCML + CST)
contralateral loss of pain and temperature (STT)

20

Where is the primary somatosensory cortex found

post central gyrus

21

Where is the primary somatomotor cortex found

pre central gyrus

22

How many neurons are involved in ascending tracts

3
1st, 2nd and 3rd order neurons

23

How many neurons are involved in descending tracts

2
UMN + LMN

24

Where do 3rd order neurons in ascending tracts synapse

thalamus in the brain

25

path of the corticobulbar tract

passes through internal capsule to reach the brainstem

26

fibres in the corticobulbar tract innervate CN nuclei bilaterally except __

CN VII
UMN of facial nerve has contralateral innervation of muscles of the lower face and bilateral innervation of muscles of the upper face
ie R brain controls left lower facial muscles
CN XII
UMN of hypoglossal has contralateral innervation to the tongue

27

central lesion of CN VII causes forehead sparing/involvement
and give an example of this

sparing
because upper facial muscles have bilateral innervation
stroke

28

peripheral lesion of CN VII causes forehead sparing/involvement
and give an example of this

involvement
Bell's palsy

29

what is the rubrospinal tract

originates in the red nucleus of the midbrain
excites upper limb flexors
inhibits upper limb extensors

30

the rubrospinal tract innervates both upper and lower limbs, true or false

FALSE
only innervates upper limbs

31

what is the reticulospinal tract

originates in pons/medulla
excites upper and lower limb extensors

32

in terms of descending tracts, what is the order of dominance over the body

1. corticospinal tract
2. rubrospinal tract
3. reticulospinal tract

33

what happens if the CST is lost

rubrospinal tract is next dominant
therefore upper limb flexion ie decorticate posturing

34

what happens is the rubrospinal tract is lost

reticulospinal tract is next dominant
therefore there is both upper and lower limb extension ie decerebrate posturing

35

fasciculus gracilis is from below/above T6

below