Spinal Cord and Periphery

Question 1

What are the 3 columns of white matter?

Answer 1

Posterior
Lateral
Anterior

Question 2

What are ascending pathways?

Answer 2

Sensory

Question 3

What are descending pathways?

Answer 3

Motor

Question 4

What is the role of the corticospinal/pyramidal tract?

Answer 4

Carries motor impulses from motor cortex to skeletal muscles

Question 5

What is the role of the posterior/dorsal column?

Answer 5

Carries touch, tactile localisation, vibration sense, proprioception

Question 6

What is the role of the lateral spinothalamic tract?

Answer 6

Pain and temperature

Question 7

Where does the pathway of the pyramidal tract start?

Answer 7

From motor cortex (area 4)

Question 8

What happens to corticobulbar fibres?

Answer 8

Go to contralateral cranial nerve nucleii

Question 9

Where do corticospinal fibres cross?

Answer 9

Decussation of pyramids

Question 10

What is the site of lower motor neurons?

Answer 10

Ventral horn

Question 11

What does the dorsal column carry?

Answer 11

Sensations of:
Fine touch
Tactile localisation
Vibration sense
Proprioception

Question 12

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

Answer 12

Synapses with the cell body of the 2nd neuron

Question 13

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

Answer 13

Lower part of the medulla

Question 14

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

Answer 14

Medulla

Question 15

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

Answer 15

Medial lemniscus

Question 16

What does the medial lemniscus pass through?

Answer 16

Medulla, pons, midbrain to reach the thalamus

Question 17

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

Answer 17

Thalamus

Question 18

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

Answer 18

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

Question 19

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

Answer 19

Enters into the grey matter and ends at the same level

Question 20

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

Answer 20

Thalamus

Question 21

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

Answer 21

Internal capsule

Radiation to reach post-central gyrus

Question 22

Where does decussation occur in the lateral spinothalamic tract?

Answer 22

At the level of entry

Question 23

What is a reflex?

Answer 23

Involuntary pattern of response in result of a sensory stimulus

Question 24

Where are reflexes mediated?

Answer 24

At the level of spinal cord

Question 25

What happens in the stretch reflex?

Answer 25

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

Question 26

Why is the stretch reflex important?

Answer 26

Important in control of muscle tone and posture

Question 27

What happens in the flexor reflex?

Answer 27

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)

Question 28

What mediates reflexes?

Answer 28

Lower motor neurons

Question 29

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

Answer 29

Reflexes are exaggerated

Question 30

How does UMN lesion and LMN lesions affect muscle tone?

Answer 30

UMN lesion = increased tone (spasticity) | LMN lesion = decreased tone (flaccidity)

Question 31

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

Answer 31

Above the level of decussation

Question 32

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

Answer 32

Signs and symptoms are ipsilateral

Question 33

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

Answer 33

Right sided paralysis Hyper-reflexia Increased tone

Question 34

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

Answer 34

Left sided paralysis Hyper-reflexia Increased tone

Question 35

What are the signs of a left LMN lesion?

Answer 35

Left sided paralysis Absent reflexes Flaccid

Question 36

Is motor neuron disease an UMN or LMN?

Answer 36

LMN

Question 37

What is MND?

Answer 37

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

Question 38

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

Answer 38

Right sided sensory loss

Question 39

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

Answer 39

Left sided sensory loss

Question 40

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

Answer 40

Right sided pain and temperature loss

Question 41

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

Answer 41

Left sided pain and temperature loss