PHYSIOLOGY - nerve pathways

Question 1

what type of input does the superior colliculus receive

Answer 1

ocular input

Question 2

what type of input does the inferior colliculus receive

Answer 2

auditory input

Question 3

what does the dorsal column (DCML) supply

is it ascending (sensory) or descending (motor)

Answer 3

fine touch and proprioception (and 2 point discrimination)

ascending (sensory

Question 4

what does the spinothalamic tract supply

is it ascending (sensory) or descending (motor)

Answer 4

pain, temperature, deep pressure

ascending (sensory)

Question 5

what does the spinoreticular tract supply

is it ascending (sensory) or descending (motor)

Answer 5

pain (slower response than spinothalamic tract)

ascending (sensory)

Question 6

what does the corticospinal tract supply

is it ascending (sensory) or descending (motor)

Answer 6

fine movements of distal limbs

descending (motor)

Question 7

what does the tectospinal tract supply

is it ascending (sensory) or descending (motor)

Answer 7

head and neck movements in response to visual stimuli

descending (motor)

Question 8

what does the vestibulospinal tract supply

is it ascending (sensory) or descending (motor)

Answer 8

balance and posture

descending (motor)

Question 9

what does the reticulospinal tract supply

is it ascending (sensory) or descending (motor)

Answer 9

flexor/extensor movements

descending (motor)

Question 10

what does the rubrospinal tract supply

is it ascending (sensory) or descending (motor)

Answer 10

excites flexor muscles and inhibits extensor muscles of upper body

descending (motor)

Question 11

what are the 3 ascending (sensory) tracts

Answer 11

dorsal column - fine touch and proprioception
spinothalamic tract - pain, temperature, deep touch
spinoreticular tract - pain (slower)

Question 12

what are the 5 descending (motor) tracts

Answer 12

corticospinal tract
tectospinal tract (head and neck movement in response to visual stimuli)
vestibulospinal tract (balance eand posture)
reticulospinal tract
rubrospinal tract

Question 13

what are the 2 tracts within the dorsal column

Answer 13

medial fasciculus gracilis (gracile tract)

lateral fasciculus cuteatus (cuneate tract)

Question 14

what does the medial fasciulus gracilis (gracile tract) part of dorsal column supply

Answer 14

lower limbs, T6 and below

THINK: the lateral nerves come off before the medial ones = medial ones supply lower down

Question 15

what does the lateral fasciculus cuneate (cuneate tract) part of the dorsal column supply

Answer 15

upper limbs, above T6

THINK: lateral nerves comes off before the medial ones = lateral ones supply upper limbs

Question 16

where do the fibres in the dorsal column dessucate (cross sides)

Answer 16

medulla

Question 17

in the medulla, which nucleus does the fasciculus gracilis synapse at

Answer 17

gracile nucleus

Question 18

in the medulla, which nucleus does the fasciculus cuneatus synapse at

Answer 18

cuneate nucleus

Question 19

after they synapse in the medulla (cuneate/gracile nucleus) where do the second order neurons of the dorsal column travel

(arrive in thalamus)

Answer 19

in the medial lemniscus (band of white matter)

Question 20

dorsal column

where are the first order neurones

Answer 20

between stimulus and medulla

Question 21

dorsal column

where are the second order neurons

Answer 21

between medulla and thalamus

Question 22

dorsal column

where are the third order neurons

Answer 22

between thalamus and primary somatosensory cortex in cerebrum

Question 23

which gyrus is the primary somatosensory cortex in

Answer 23

post central gyrus (just behind the central sulcus)

Question 24

which part of the somatosensory cortex is most medial (info from which part of the body)

Answer 24

feet

Question 25

which part of the somatosensory cortex is most lateral (info from which part of the body)

Answer 25

head

Question 26

what is the 'man' called that represents what the body would look like if each art was in proportion to its sensory input

Answer 26

homunculus

Question 27

how would you test is the dorsal column was working or not (2)

Answer 27

fine touch | proprioception

Question 28

what does the spinothalamic tract (STT) do

Answer 28

relays pain, temperature and deep pressure info to brain

Question 29

where do the fibres dessucate (cross) in the STT

Answer 29

in the spinal cord NOT medulla like the dorsal column

Question 30

do dorsal column and STT fibers enter the spinal cord via white or grey matter

Answer 30

entire via grey matter then travel up spinal cord in white matter

Question 31

which spinal tract is also known as the pyramidal tract

Answer 31

corticospinal tract

Question 32

which tract travels along side the corticospinal tract in the pyramids of the medulla to supply motor nerves to the face

Answer 32

corticobulbar tract

Question 33

where do the fibres in the corticospinal tract originate

Answer 33

primary motor cortex

Question 34

which gyrus is the primary motor cortex in

Answer 34

precentral gyrus THINK: motor fibres want to get close to the action = more anterior gyrus

Question 35

what % of fibres dessucate (cross) at the medulla in the corticospinal tract what is this subtype of the tract called

Answer 35

85% lateral corticospinal tract

Question 36

what % of fibres dessucate (Cross) in the spinal cord in the corticospinal tract what is this subtype of the tract called

Answer 36

15% anterior corticospinal tract

Question 37

where do the lateral corticospinal tract fibres dessucate

Answer 37

medulla

Question 38

where do the anterior coritcospinal tract dessuctae

Answer 38

spinal cord

Question 39

which spinal tract has bilateral supply what is the clinical significance of this

Answer 39

corticobulbar (to the face) UMN lesion = bilateral problem (though not complete paralysis bc of the other sided supply) LMN lesion = unilateral problem (paralysis)

Question 40

where do the fibres for the tectospinal tract originate

Answer 40

superior colliculus cortex

Question 41

where does the sensory input for the tectospinal tract come from

Answer 41

occular input tectospinal tract = moves head and neck in response to a visual stimuli

Question 42

where does the fibres from the tectospinal tract leave the spinal cord

Answer 42

C1-C8 bc they supply the head/neck etc

Question 43

what are the 2 origins of the 2 reticulospinal tracts

Answer 43

pons | medulla

Question 44

where does the fibres form the vestibulospinal tract originate

Answer 44

vestibular nuclei (in pons)

Question 45

where does the sensory input for the vestibulospinal tract come from

Answer 45

vestibular apparatus and cerebellum bc it controls muscles of balance

Question 46

is the supply of the vestibulospinal tract bilateral, ipsilateral or controlateral

Answer 46

ipsilateral THINK: bc the cerebellum has ipsilateral control

Question 47

where is the primary auditory cortex

Answer 47

superior temporal lobe, just under the lateral fissure

Question 48

is it wernickes or brocas area that is near the primary auditory cortex in the superior temporal lobe (just under the lateral fissure)

Answer 48

wernickes THINK: bc brocas = broken language, then wernickes must be unable to understand language = auditory processing problem

Question 49

why does alcohol make you dizzy

Answer 49

alcohol is lighter than water = crystals more likely to sink = activates hair cells

Question 50

in right handed people, which hemisphere is dominant for language (hence contains wernickes and brocas areas)

Answer 50

left hemisphere

Question 51

which ascending tract recognises 2 point discrimination

Answer 51

dorsal column (probs bc it does proprioception)

Question 52

which descending pathway is pyramidal by default, what does that make the rest of them...

Answer 52

corticospinal tract rest = extrapyramidal