Ascending and descending pathways Flashcards

1
Q

Ascending pathways are sensory / motor ?

A

Sensory

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2
Q

Sensory information travels to which part of the brain?

A

Primary somatosensory cortex

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3
Q

Where in the brain is sensory information interpreted?

A

Post central gyrus

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4
Q

How is the primary somatosensory cortex arranged?

A

By mapping out the body onto the cortex via the somatosensory strip.
- this gives rise to the homunculus

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5
Q

At what location do sensory fibres cross the midline?

A

In the medulla

- i.e. the left side of the boy is represented on the right side

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6
Q

Name 2 ascending pathways

A

Dorsal column medial lemniscus (DCML)

Spinothalamic tract

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7
Q

Which sensory pathway conveys fine touch, pressure, vibration and conscious proprioception?

A

DCML tract

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8
Q

Sensory information travels up the grey matter of the spinal cord. True or false?

A

False

- white matter

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9
Q

Which sensory pathway conveys pain, temperature, deep pressure signals?

A

Spinothalamic tract

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10
Q

DCML tract - where does decusation occur?

A

Medulla

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11
Q

DCML tract - first order neurones

A

Carry sensory info from the peripheral nerves to the medulla

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12
Q

DCML tract - signals from the upper limb (above T6) travel in the fasciculus GRACILIS / CUNEATUS ?

A

Fasciculus cuneatus

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13
Q

DCML tract - signals from the lower limb (T6 and below) travel in the fasciculus GRACILIS / CUNEATUS ?

A

Fasciculus gracilis

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14
Q

DCML tract - second order neurones

A

Begin in nucleus cuneatus/gracilis in the medulla.

They deliver information to the third order neurones by crossing over to the other side of the CNS.

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15
Q

DCML tract - where are third order neurones located?

A

In the thalamus

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16
Q

DCML tract -third order neurones transmit sensory signals from the thalamus to the IPSILATERAL/CONTRALATERAL primary somatosensory cortex

A

Ipsilateral

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17
Q

Spinothalamic tract - where does decusation occur?

A

Spinal cord level

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18
Q

Spinothalamic tract - first order neurones

A

Arise from the peripheral sensory receptors and synapse occurs at spinal cord

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19
Q

Spinothalamic tract - second order neurones carry information from spinal cord level to _____

A

thalamus

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20
Q

Spinothalamic tract - fibres ascend the spinal cord within the IPSILATERAL/CONTRALATERAL tract?

A

Contralateral

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21
Q

Spinothalamic tract - third order neurones carry signals from the thalamus to the IPSILATERAL/CONTRALATERAL primary somatosensory cortex

A

Ipsilateral

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22
Q

A spinal cord lesion is likely to be associated with ipsilateral/contralateral signs and symptoms?

A

Contralateral

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23
Q

Descending pathways are sensory/motor ?

A

Motor

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24
Q

LMNs directly innervate muscles to produce movement. True or false?

A

True

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25
Q

Where is the primary motor cortex located?

A

In the dorsal portion of the frontal lobe

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26
Q

The right motor cortex controls muscles on the right/left side of the body?

A

Left

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27
Q

Name 4 descending pathways

A

Corticospinal tract (pyrimidal)
Tectospinal tract
Reticulospinal tract
Vestibulospinal tract

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28
Q

Which pathway is responsible for fine control - fine, precise movements, particular in the distal limb muscles

A

Corticospinal tract

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29
Q

Corticospinal tract controls voluntary body movements. True or false?

A

True

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30
Q

Corticospinal tract - decussation of most motor fibres occurs where?

A

Medullary pyramids

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31
Q

Corticospinal tract - what structures do fibres cross through to get to the spinal cord?

A

Internal capsule -> midbrain -> spinal cord

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32
Q

Internal capsule occlusion can block the corticospinal tract and cause which movement in the upper limbs?

A

Spastic paralysis with hyeprflexion

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33
Q

Which 4 tracts make up the extrapyramidal system?

A

Tectospinal tract
Reticulospinal tract
Rubrospinal tract
Vestibulospinal tract

34
Q

Tectospinal tract - which region of the spine does it work on?

A

Cervical region

35
Q

Tectospinal tract - function

A

Visual and auditory function

Important in tracking functions

36
Q

Tectospinal tract only projects to the upper limbs. True or false?

A

True

37
Q

Reticulospinal tract - function

A

Many autonomic functions of the body

Voluntary movement

38
Q

Vestibulospinal tract - function

A

Detects movement

Controls balance and posture

39
Q

Which of the 3 extrapyramidal tracts does not cross over?

A

Vestibulospinal tract

40
Q

Sensory travels from the periphery to the primary somatosensory cortex. This information is then interpreted where ?

A

Post central gyrus

41
Q

DCML tract - fasciculus gracilus is medial or lateral to fasciculus cuneatus?

A

Medial

42
Q

DCML tract - the fibres ascend up the DCML tract of the spinal cord ipsilateral/contralateral to the side they enter?

A

Ipsilateral

- decussation doesn’t occur until the medulla

43
Q
DCML tract - first order neurone primary sensory fibres are which 2 of the following: 
A beta
C fibres 
A delta 
A alpha
A

A alpha

A beta

44
Q

Which vertebral level is the cut off between fasciculus cuneatus and gracilis?

A

T6

  • above T6 = cuneatus
  • T6 and below = gracilis
45
Q

DCML - up until the brainstem, information coming from the body is ipsilateral/contralateral?

A

Ipsilateral

46
Q

DCML - after decusation in the brainstem, information is represented ipsilaterally/contralaterally ?

A

Contralaterally

47
Q

DCML - how does information from the 3rd order neurone get from the thalamus -> primary somatosensory cortex?

A

Via posterior internal capsule

48
Q

Sensory information from which part of the body does not travel via the DCML pathway?

A

Anterior head

49
Q

DCML pathway : which side is most lateral and which side is most medial:
Cervical -> thoracic -> lumbar -> sacral

A
Cervical = lateral 
Sacral = medial
50
Q

As we ascend the spinal cord, the ratio of white:grey matter increases/decreases?

A

Increases

51
Q
Spinothalamic tract - first order neurone primary sensory fibres are which 2 of the following: 
A beta
C fibres 
A delta 
A alpha
A

A delta

C fibres

52
Q

Spinothalamic tract - location of the tract?

A

Anterolateral

53
Q

Spinothalamic tract - carries information from the opposite side of the body. True or false?

A

True

54
Q

Which pathway provides unconscious proprioceptive information to the cerebellum (and is therefore important in motor co-ordination)?

A

Spinocerebellar pathway

55
Q

Spinocerebellar pathway - information is transmitted to the ipsilateral/contralateral cerebellum?

A

Ipsilateral

56
Q

Both DCML and spinothalamic tracts transmit information to the contralateral somatosensory cortex. True or false?

A

True

57
Q

Name the 3 spinocerebellar tracts

A

Dorsal spinocerebellar tract
Ventral cerebellar tract
Cuneocerebellar tract

58
Q

Which spinocerebellar tract carries unconscious proprioceptive information from the upper limbs?

A

Cuneocerebellar tract

59
Q

Which spinocerebellar tract carries unconscious proprioceptive information from the lower limbs?

A

Dorsal spinocerebellar tract

60
Q

Which spinocerebellar tract decussates twice?

A

Ventral spinocerebellar tract

61
Q

Trigeminal system - where does the synapse occur for general tactile information of the anterior head ?

A

In the main sensory nucleus

62
Q

Trigeminal system - where does the synapse occur for pain, temperature information of the anterior head?

A

Spinal nucleus

63
Q

Where do descending spinal tracts arise from?

A

Cerebral cortex and brain stem

64
Q

Descending pathways - name 2 lateral pathways

A

Lateral corticospinal tract

Rubrospinal tract

65
Q

Descending pathways - lateral pathways are under control from the cerebral cortex / brainstem ?

A

Cerebral cortex

66
Q

Descending pathway - lateral pathway is important for voluntary control of distal musculature. True or false?

A

True

67
Q

Descending pathways - name 3 ventromedial tracts

A

Pontine (medial) reticulospinal tract
Medullary (lateral) reticulospinal tract
Lateral vestibulospinal tract

68
Q

Lateral corticospinal tract contain decusated fibres. True or false?

A

True

69
Q

Vental corticospinal tract contain decusated fibres. True or false?

A

False

- undecusated

70
Q

Lateral corticospinal tract supplies more proximal/distal limbs ?

A

Distal

71
Q

In the corticospinal tract, the upper limb fibres are more MEDIAL/LATERAL and the lower limb fibres are more MEDIAL/LATERAL

A

Upper limb fibres - medial

Lower limb fibres - lateral

72
Q

What tract contains the UMN of the cranial nerves to provide innervation of the face, head and neck ?

A

Corticobulbar tract

73
Q

Corticobulbar tracts innervate cranial motor nuclei unilaterally/bilaterally?

A

Bilaterally

- there are exceptions (hypoglossal nuclei and lower facial nuclei which are innervated contra laterally only)

74
Q

UMN lesion of facial nerve will cause paralysis where?

A

Lower half of one side of the face only and the forehead muscles remain unaffected

75
Q

LMN lesion of facial nerve will cause paralysis where?

A

Paralysis of the ipsilateral one half of the face including the forehead (Bell’s palsy)

76
Q

Function of the rubrospinal tract?

A

Excites flexor muscles and inhibits extensor muscles of the upper body

77
Q

There is no decussation of the vestibulospinal tract. True or false?

A

True

78
Q

Cell bodies of the tectospinal tract originate where?

A

Superior colliculus in the midbrain

79
Q

Which tract co-ordinates movements of the head due to visual stimuli?

A

Tectospinal tract

80
Q

What is the reticular formation?

A

Mesh of neurone that are located along the length and at the core of the brainstem

81
Q

Pontine (medial) reticulospinal tract descends ipsilaterally/bilaterally?

A

Ipsilaterally

82
Q

Medullary (lateral) reticulospinal tract descends ipsilaterally/bilaterally?

A

Bilaterally