Spinal Cord and Periphery Flashcards

1
Q

What are the 3 columns of white matter?

A

Posterior
Lateral
Anterior

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2
Q

What are ascending pathways?

A

Sensory

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3
Q

What are descending pathways?

A

Motor

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4
Q

What is the role of the corticospinal/pyramidal tract?

A

Carries motor impulses from motor cortex to skeletal muscles

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5
Q

What is the role of the posterior/dorsal column?

A

Carries touch, tactile localisation, vibration sense, proprioception

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6
Q

What is the role of the lateral spinothalamic tract?

A

Pain and temperature

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7
Q

Where does the pathway of the pyramidal tract start?

A

From motor cortex (area 4)

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8
Q

What happens to corticobulbar fibres?

A

Go to contralateral cranial nerve nucleii

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9
Q

Where do corticospinal fibres cross?

A

Decussation of pyramids

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10
Q

What is the site of lower motor neurons?

A

Ventral horn

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11
Q

What does the dorsal column carry?

A
Sensations of:
Fine touch
Tactile localisation
Vibration sense
Proprioception
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12
Q

How does the 1st order neuron end? (dorsal column)

A

Synapses with the cell body of the 2nd neuron

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13
Q

Where is the cell body of the 2nd neuron situated? (dorsal column)

A

Lower part of the medulla

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14
Q

Where does the 2nd order neuron cross over? (dorsal column)

A

Medulla

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15
Q

What is the tract known as after the 2nd order neuron decussates? (dorsal column)

A

Medial lemniscus

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16
Q

What does the medial lemniscus pass through?

A

Medulla, pons, midbrain to reach the thalamus

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17
Q

Where does the 3rd order neuron start? (dorsal column)

A

Thalamus

18
Q

Where do axons of the 3rd order neuron pass? (dorsal column)

A

Axons pass through the internal capsule and radiate to the post-central gyrus (Area 2, 1, 3)

19
Q

Where does the first order neuron enter and end? (lateral spinothalamic tract)

A

Enters into the grey matter and ends at the same level

20
Q

Where does the 2nd order neuron end? (lateral spinothalamic tract)

A

Thalamus

21
Q

Where does the 3rd order neuron pass through? (lateral spinothalamic tract?

A

Internal capsule

Radiation to reach post-central gyrus

22
Q

Where does decussation occur in the lateral spinothalamic tract?

A

At the level of entry

23
Q

What is a reflex?

A

Involuntary pattern of response in result of a sensory stimulus

24
Q

Where are reflexes mediated?

A

At the level of spinal cord

25
Q

What happens in the stretch reflex?

A
  1. tendon stretched
  2. intrafusal muscle fibres stimulated
  3. sensory neuron activated
  4. monosynaptic reflex arc
    - polysynaptic reflex arc to inhibitory interneuron
  5. muscle contraction
    - reciprocal innervation
26
Q

Why is the stretch reflex important?

A

Important in control of muscle tone and posture

27
Q

What happens in the flexor reflex?

A
  1. pain stimulus
  2. sensory neuron activated
  3. polysynaptic reflex arc
  4. flexion and withdrawal from noxious stimulus
    - crossed extensor response to contralateral limb (only in weight bearing limbs)
28
Q

What mediates reflexes?

A

Lower motor neurons

29
Q

What happens to reflexes when there is an UMN lesion with LMN unaffected?

A

Reflexes are exaggerated

30
Q

How does UMN lesion and LMN lesions affect muscle tone?

A

UMN lesion = increased tone (spasticity)

LMN lesion = decreased tone (flaccidity)

31
Q

Where is a lesion located the signs and symptoms are contralateral?

A

Above the level of decussation

32
Q

What happens if a lesion is below the level of decussation?

A

Signs and symptoms are ipsilateral

33
Q

What are the signs of a left UMN lesion at the internal capsule?

A

Right sided paralysis
Hyper-reflexia
Increased tone

34
Q

What are the signs of a left UMN lesion at the upper cervical spinal cord?

A

Left sided paralysis
Hyper-reflexia
Increased tone

35
Q

What are the signs of a left LMN lesion?

A

Left sided paralysis
Absent reflexes
Flaccid

36
Q

Is motor neuron disease an UMN or LMN?

A

LMN

37
Q

What is MND?

A

A group of diseases affecting the LMN in the ventral horn of the spinal cord
Neuron dies = muscle atrophy

38
Q

What would happen if there was a lesion in the left internal capsule affecting the dorsal column?

A

Right sided sensory loss

39
Q

What would happen if there was a lesion at left cervical spinal cord affecting the dorsal column?

A

Left sided sensory loss

40
Q

What would happen with a lesion in the left internal capsule affecting the lateral spinothalamic tract?

A

Right sided pain and temperature loss

41
Q

What would happen with a lesion in the left cervical spinal cord affecting the lateral spinothalamic tract?

A

Left sided pain and temperature loss