Spinal Cord Pathways

Question 1

Where are the 2 enlargements of the spinal cord?

Answer 1

Cervical (ie. brachial plexus) and lumbar (ie. lumbosacral plexus)

Question 2

How does the cauda equine develop?

Answer 2

The nerve roots coming out of the base of the spine grow to become fibers – we cean draw CSF from this space without worrying about hitting the spinal cord.

Question 3

How is the grey/white matter arrangement different in the spinal cord different from the cerebrum?

Answer 3

In the spinal cord, the white matter is on the outside

Question 4

The ___ ___ horns join up to make dorsal/ventral ____, which make up the spinal nerve.

Answer 4

grey matter horns, dorsal/ventral roots

Question 5

What does the dorsal column/medial leminiscus pathway do?

Answer 5

joint/limb position and proprioception, light toucch

Question 6

what does the spinothalamic (anterolateral) pathway do?

Answer 6

pain/temperature, deep touch (pressure)

Question 7

what does the spinocerebellar pathway do?

Answer 7

unconscious proprioception

Question 8

The dorsal column crosses over to the ipsilateral side at the ____.

Answer 8

medulla

Question 9

The spinothalamic pathway crosses over to the ipsilateral side at the ____.

Answer 9

medulla

Question 10

The spinocerebellar pathway crosses over to the ipsilateral side at the ____.

Answer 10

pons

Question 11

Somatic motor pathways involve at least ___ motor neurons: _______

Answer 11

2: upper and lower

Question 12

What happens when the upper motor neuron is damaged and can no longer inhibit the lower motor neuron?

Answer 12

the muscle continues to contract & seize up (spastic paralysis)

Question 13

What happens when the lower motor neuron is damaged and can no longer deliver information to the periphery?

Answer 13

The muscle can’t contract, going limp (flaccid paralysis)

Question 14

What does the corticospinal pathway regulate?

Answer 14

the limbs & trunk

Question 15

What does the corticonuclear pathway regulate?

Answer 15

the head & neck

Question 16

What are extrapyramidal pathways used for?

Answer 16

back-up systems in the case of pyramidal pathway damage

Question 17

Which areas of the brain are activated for simple finger flexion?

Answer 17

the motor cortex & somatic sensory cortex

Question 18

Which areas of the brain are activated for finger movement sequencing?

Answer 18

motor cortex & premotor & supplementary motor area

Question 19

Which areas of the brain are activated for finger sequence mental rehearsal?

Answer 19

premotor & supplementary motor area

Question 20

What is the internal capsule?

Answer 20

Where all motor fibers come together and bundle in the brain

Question 21

__% of axons cross over to the other side of the spinal cord as they travel down the corticospinal pathway.

Answer 21

85%

Question 22

What happens if you have damage above the level of the midbrain?

Answer 22

the red nucleus is uninhibited & you lock up

Question 23

What happens if you have damage below the level of the midbrain?

Answer 23

you can move freely, but that means RAS damage which involves becoming unconscious