Spianl Cord And Periphery

Question 1

What composes white and grey matter?

Answer 1

Grey matter is neuronal cell bodies (inside CNS = nucleii, outside CNS = ganglia)

White matter is tracts of axons

Question 2

What does the corticospinal / pyramidla tract carry ?

Answer 2

Motor fibres from the motor cortex to skeletal muscle

Question 3

What does the lateral spinothalamic tract carry and to where?

Answer 3

Sensory - pain and touch

Question 4

What does the posterior/dorsal column carry and to where?

Answer 4

Sensory fibres - touch, localisation and vibration sense

Question 5

What’s the difference in the neuronal pathways between tracts which carry motor and ones which carry sensory fibres?

Answer 5

Motor pathway involves 2 neurones which synapse after one leaves the spinal cord

Sensory pathway involves 3 neurones which synapse between the peripheral receptor and the cortex

Question 6

What are the 2 point where sensory neurones synapse?

Answer 6

The grey matter of spinal cord (lateral spinothalamic tract) or nucleus in the medulla (posterior/dorsal column)

The nucleus in the contractural thalamus after the decussation of pyramids

Question 7

Specifically where does motor neurones which enter the corticospinal tract originate from?

Answer 7

Area 4 - the motor cortex

Question 8

In the posterior dorsal column where does the 1st neurone synapse with the 2nd neurone?

Answer 8

Lower part of the medulla (before the decussation)

Question 9

What is the posterior / dorsal column called after the fibres cross at the decussation?

Answer 9

The medial Lemniscus

Question 10

In the posterior dorsal colum, where does the 3rd neurone begin and go to?

Answer 10

Starts from the thalamus and the axons pass through the internal capsule and radiate to the post-central gyrus (area 3,1,2)

Question 11

A lesion to the posterior dorsal column fibres above the decussation will cause what affects?

Answer 11

Contralateral sensory loss

Question 12

Damage to posterior dorsal column on the right side, below the level of the decussation, will cause what affects?

Answer 12

Sensory loss of the right side

Question 13

What does the lateral spinothalamic tract carry?

Answer 13

Sensory fibres for pain and temperatures

Question 14

Where are the synapses of the neurones in the lateral spinothalamic tract?

Answer 14

1st synapses at the level of entry

2nd synapses at the thalamus

Question 15

Where does the 3rd order neurone of the lateral spinothalamic tract take the neurones?

Answer 15

Passes through the internal capsule and radiates to the post central gurus (Areas 3,1,2)

Question 16

Within what tract does the decussation occur at the level of entry?

Answer 16

The lateral spinothalamic tract

Question 17

Why are reflexes involuntary?

Answer 17

The nerve impulses travel and synapse at the spinal cord and don’t go to the brain

Question 18

Name a reflex which is;

1) monosynaptic
2) polysnaptic

Answer 18

1 = stretch reflex 
2 = flexor reflex

Question 19

What is the function of the stretch and flexor reflex?

Answer 19

Stretch reflex important in control of muscle tone and posture

Flexor reflex important in protecting the body from painful stimuli

Question 20

In which type of motor neurone lesion causes hyperreflexia?

Answer 20

Upper motor neurone lesion

Question 21

In which motor neurone lesion causes spasticity?

Answer 21

Upper motor neurone lesion