Spinal Cord: Ascending tracts & sensation Flashcards

1
Q

List 5 types of receptors in the hand.

A

Meissner corpuscle

Pacinian corpuscle

Ruffini ending

Merkel discs

Free nerve endings

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2
Q

What do Meissner corpuscles detect?

A

Discriminative touch

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3
Q

What do Pacinian corpuscles detect?

A

Deep pressure & vibration

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4
Q

What 2 things do Ruffini endings detect?

A

Touch
Sheer stress / forces

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5
Q

What do Merkel discs detect?

A

Light, sustained touch

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6
Q

What do free nerve endings detect?

A

Pain & temperature

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7
Q

Which brain area is responsible for integration of sensory inputs, sensory memory, perception of contralateral self/ world

A

Superior parietal lobe

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8
Q

What does the anterior limb of the internal capsule contain?

A

Descending fibres (frontopontine + frontothalamic)

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9
Q

What 2 things does the genu and posterior limb of the internal capsule contain?

A

Motor fibres to the head, arm, leg
Sensory fibres

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10
Q

What 2 things does the retrolenticular part of the internal capsule contain?

A

Visual input
Auditory input

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11
Q

Describe the route of each neuron in the 3 neuron ascending sensory pathway.

A

1st order neuron – enters spinal cord via dorsal root, ascends ipsilaterally

2nd order neuron – decussates + ascend to the thalamus

3rd order neurons – leave thalamus to ascend to cortex via internal capsule

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12
Q

What are the 2 main nuclei in the thalamus for sensory input?

A

Ventral posterior lateral nucleus (VPL)

Ventral posterior medial nucleus (VPM)

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13
Q

The VPL nucleus in the thalamus receives sensory input from what?

A

Body

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14
Q

The VPM nucleus in the thalamus receives sensory input from what?

A

Face

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15
Q

What are the 4 sensory tracts?

A

Dorsal column pathway

Spinothalamic tract

Spinocerebellar tract

Trigeminothalamic tract

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16
Q

The dorsal column pathway receives sensory input from which 5 receptors?

A

Meissner’s
Merkel’s
Pacinian
Ruffini
Joint proprioceptors

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17
Q

The dorsal column pathway receives which 2 kinds of sensory input?

A

Discriminative touch & vibration

Conscious proprioception

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18
Q

The spinothalamic tract receives sensory input from which receptors?

A

Free nerve endings

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19
Q

The spinothalamic tract receives which 3 kinds of sensory input?

A

Pain + temperature
Simple touch

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20
Q

The spinocerebellar tract receives sensory input from which 2 receptors?

A

Muscle spindles

Golgi tendon organs

21
Q

The spinocerebellar tract receives which kind of sensory input?

A

Unconscious proprioception

22
Q

What are the 2 sections of the dorsal column pathway and from which vertebral levels do they receive fibres from?

A

Fasciculus gracilis – from below T6

Fasciculus cuneatus – from above T6

23
Q

Where do 2nd order neurons in the dorsal column pathway decussate?

24
Q

What are 2nd order neurons in the dorsal column pathway called after they decussate?

Which nucleus do they ascend to?

A

Medial lemniscus – which ascends to VPL nucleus of the thalamus

25
Via what tract does sensory information from the face reach the brain?
Trigeminothalamic tract
26
Where do 1st order neurons of the trigeminothalamic tract enter the brainstem?
Pons
27
What are 2nd order neurons in the trigeminothalamic tract called after they decussate? Which nucleus do they ascend to?
Trigeminal lemniscus – which ascends to VPM nucleus of the thalamus
28
Describe the loss of sensation that would occur if the dorsal column pathway was damaged?
Ipsilateral loss of sensation below the level of the lesion
29
Which STD can damage the dorsal column pathway?
Tertiary syphilis
30
Which 2 conditions might result from dorsal column damage? These are caused by the loss of which specific sensory input?
Pseudoathetosis – writhing of digits, hands, and feet Sensory ataxia – leads to positive Romberg sign & stamping gait Caused by a loss of proprioception
31
1st order neurons in the spinothalamic tract enter the spinal cord via what?
Tract of Lissauer
32
Where do 2nd order neurons in the spinothalamic tract decussate?
1-2 vertebral levels above the entry into the spinal cord
33
2nd order neurons in the spinothalamic tract decussate across what?
Anterior white commissure
34
The spinothalamic tract route can be damaged by which condition that typically occurs in the cervical vertebrae?
Syringomyelia – cavitation of the central canal which damages the anterior white commissure
35
Describe the somatotopic organization of the spinothalamic tract, beginning from the centre and going outwards.
Neck Arm/thorax Leg Sacral
36
Due to the direction it is likely to grow, a spinothalamic tract tumour can spare which region?
Sacrum – sacral sparing
37
The dorsal spinocerebellar tract receives input from what?
Muscle spindles
38
The ventral spinocerebellar tract receives input from what?
Golgi tendon organs
39
Does the spinocerebellar tract carry sensory to the ipsilateral or contralateral cerebellum?
Ipsilateral
40
Although it is rare for the spinocerebellar tract to be damaged in isolation, in which condition can this occur?
Friedreich’s ataxia – autosomal recessive condition
41
Where is sensory to the genitals and foot / leg located on the somatotopic map of the brain?
In between the cerebral hemispheres
42
Where is sensory to the face located on the somatotopic map of the brain?
Lateral cerebral hemispheres
43
Where is sensory to the hand located on the somatotopic map of the brain?
Superolateral cerebral hemispheres
44
In sensory pathways, which order neuron decussates?
2nd order neuron
45
Syringomyelia typically occurs in which vertebrae?
Cervical
46
A cape shaped loss of pain + temperature is a symptom of which condition?
Syringomyelia
47
How many neurons in the spinocerebellar tract?
2
48
What type of sensation do muscle spindles detect?
Stretch
49
What type of sensation do golgi tendon organs detect?
Force