3 - Somatosensory system 2 Flashcards

1
Q

Which arteries supply the dorsal column?

A

Posterior spinal arteries (x2)

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2
Q

Which artery supplies the majority of the spinal cord (except dorsal column) ?

A

Anterior spinal artery

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3
Q

What are the 2 main ascending sensory tracts of the somatosensory system?

A

1) Dorsal Column Medial Lemniscus pathway (DCML)

2) Spinothalamic pathway

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4
Q

Which somatic senses are transported via the DCML pathway?

A
  • Light touch
  • Vibration
  • Proprioception
  • 2-point discrimination
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5
Q

Which somatic senses are transported via the spinothalamic pathway?

A
  • Pain
  • Crude touch
  • Temperature
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6
Q

Describe the path of the 1st order neurones of the DCML pathway:

A

From origin to medulla

up spinal cord ipsilateral to the side of origin

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7
Q

Describe the path of the 2nd order neurones of the DCML pathway:

A

From medulla to thalamus

Decussate at medulla

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8
Q

Describe the path of the 3rd order neurones of the DCML pathway:

A

From thalamus to post-central gyrus

via internal capsule

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9
Q

Where do the neurones of the DCML pathway decussate?

A

Medulla

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10
Q

If a 1st order neurone entered the DCML pathway from the hand, where would it lie in the spinal cord compared to a neurone from the foot?

A

More laterally

Cervical neurones lie most laterally, sacral lie most medially

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11
Q

Describe the path of the 1st order neurones of the spinothalamic pathway:

A

From origin, enters spinal cord and synapses a few levels above

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12
Q

Describe the path of the 2nd order neurones of the spinothalamic pathway:

A

From distal spinal cord, decussates immediately, ascends CONTRALATERAL to site of origin, to thalamus

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13
Q

Describe the path of the 3rd order neurones of the spinothalamic pathway:

A

From thalamus to post-central gyrus

via internal capsule

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14
Q

If a 1st order neurone entered the spinothalamic pathway from the hand, where would it lie in the spinal cord compared to a neurone from the foot?

A

More medially

Cervical neurones lie most medially, sacral lie most laterally

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15
Q

Which fibres carry pain?

A

C fibres

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16
Q

Which fibres carry mechanoreceptor impulses?

A

A fibres

17
Q

If you bang your knee, why does rubbing it make it less painful?

A
Descending control of pain:
Rubbing
= activation of mechanoreceptors
= activated A fibres
= excite inhibitory enkephalinergic interneurones in spinal cord
= bind to u-opioid receptor
= inhibit spinothalamic tract
18
Q

Name some causes of insensitivity to pain:

A
  • Congenital insensitivity to pain
  • Trauma
  • Diabetes
  • Chronic kidney disease
  • Chronic liver disease
  • Excessive alcohol intake
  • Cancers
  • Hypothyroidism
  • Acromegaly
  • Guillian-Barre syndrome
  • Inf: Shingles, HIV, Lyme disease
  • AI: RA, SLE
  • Drugs: Chemotherapy, HIV tx