T2 L2: Ascending and descending tracts of the spinal cord

Question 1

What is found at the dorsal horn of grey matter?

Answer 1

Neurones receiving sensory input

Question 2

What is found at the lateral horn of grey matter?

Answer 2

Preganglionic sympathetic neurones of the thorax only

Question 3

What if found at the ventral horn of grey matter?

Answer 3

Motor neuronal cell bodies

Question 4

What type of neurone is found between/within levels of the spinal chord

Answer 4

Interneurons

Question 5

What is meant by tracts?

Answer 5

Axons travelling up or down in the spinal chord

Question 6

What type of sensory information do ascending tracts carry?

Answer 6

Afferent (sensory) impulses to the centres within the brain

Question 7

What type of sensory information do descending tracts carry?

Answer 7

Efferent (motor) impulses from centres within the brain

Question 8

What type of tracts does the dorsal column contain?

Answer 8

Ascending tracts

Question 9

What type of tracts does the lateral column contain?

Answer 9

Descending and ascending tracts

Question 10

What type of tracts does the ventral column contain?

Answer 10

Descending tracts

Question 11

What is proprioceptive information?

Answer 11

Originating from within the body Eg, muscles, joints, tendons

Question 12

What is Exteroceptive information?

Answer 12

Originating from outside the body Eg, pain, temperature, tough

Question 13

What 2 types of information do ascending tracts carry?

Answer 13

Proprioceptive and exteroceptive sensory

Question 14

Which neuron of an ascending circuit enters the spinal cord via the dorsal root?

Answer 14

The first order (primary sensory) neuron

Question 15

Which neuron out of an ascending circuit ascends the spinal cord or brainstem?

Answer 15

The second order neuron

Question 16

Which neuron out of an ascending circuit projects into the cortex?

Answer 16

The third order neuron

Question 17

What do cutaneous mechanoreceptors detect?

Answer 17

Fine tough/ vibration

Question 18

What do muscle spindles detect?

Answer 18

Stretch. They tell the brain how much and how fast a muscle is lengthened or shortened. Proprioception

Question 19

What do Golgi tendon organs detect?

Answer 19

Tension on the muscle. Proprioception

Question 20

Where is the Fasciculus gracilis?

Answer 20

It’s medial

Question 21

What is the DCML pathway?

Answer 21

The Dorsal column-medial lemniscus pathway. It’s a sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, two-point discrimination, and proprioception (position) from the skin and joints.

Question 22

Where is the Fasciculus cuneatus?

Answer 22

It’s lateral

Question 23

What do first-order neurones do when they reach the spinal cord in the DCML pathway?

Answer 23

They ascend the dorsal column

Question 24

What is the difference between fasciculus Gracilis and Cuneatus?

Answer 24

Cuneatus is associated with higher extremities and Gracilis is to do with the lower. There is no Fasciculus below the mid-thoracic spinal cord

Question 25

Where do first-order neurones synapse in the DCML pathway?

Answer 25

On second-order neurones in the medulla

Question 26

Where does Fasciculus Gracilis terminate?

Answer 26

In the nucleus Gracilis (Gracile) found on the Gracile tubercle in the medulla

Question 27

Where does Fasciculus Cuneatus terminate?

Answer 27

In the nucleus Cunteatus (Cuneate) found on the Cuneate tubercle in the medulla

Question 28

Where do second-order neurones cross in the DCML pathway?

Answer 28

In the thalamus and then ascend to the thalamus

Question 29

What is the medial lemniscus?

Answer 29

The area where the second-order neurones cross before they reach the cortex

Question 30

Where do third-order neurones project?

Answer 30

From the thalamus to the somatosensory cortex

Question 31

What is multiple sclerosis?

Answer 31

An autoimmune disease that causes destruction of the brain and nerves

Question 32

What is sensory ataxia?

Answer 32

Loss of coordination and balance due to lack of proprioceptive input

Question 33

What is Romberg's sign?

Answer 33

Severe swaying on standing with eyes closed and feet together

Question 34

What does a lesion on one side of the dorsal column of the DCML pathway of the spinal cord cause?

Answer 34

Loss of tactile discrimination and proprioception on the same side

Question 35

What is the Spinothalamic tract for?

Answer 35

Pain from nociceptors, temperature, and course non-discriminative touch

Question 36

What happens to first-order neurones when they reach the spinal cord in the Spinothalamic tract?

Answer 36

They enter the dorsal horn and form the tract of Lissauer

Question 37

Where do first-order neurones in the Spinothalamic tract synapse?

Answer 37

In the dorsal horn with second-order neurones

Question 38

Where do second-order neurones of the Spinothalamic tract cross?

Answer 38

In the dorsal horn at each level

Question 39

Where do second-order neurones ascend in the Spinothalamic tract?

Answer 39

In the anterolateral column towards the thalamus

Question 40

Information from which limbs is carried in the lateral anterolateral column in the Spinothalamic tract?

Answer 40

Fibres from the lower limbs

Question 41

Information from which limbs is carried in the medial anterolateral column in the Spinothalamic tract?

Answer 41

Fibres from the medial tract (lower limbs)

Question 42

What are the side effects of damage to the anterolateral column by a lesion on one side of the spinal cord?

Answer 42

Loss of pain, temperature sensation and crude touch on the opposite side

Question 43

What would the symptoms of outer tract injury in the anterolateral column cause?

Answer 43

Loss of lower limb pain first because the fibres sit laterally

Question 44

Which part of the anterolateral column would a herniated disk affect?

Answer 44

The outer tract

Question 45

What would the symptoms of inner tract injury in the anterolateral column cause?

Answer 45

Loss of upper limb pain because the fibres sit medially

Question 46

Which part of the anterolateral column would be injured with a grey matter tumour?

Answer 46

The medial part

Question 47

What are the spinocerebellar tracts for?

Answer 47

Unconscious muscle proprioception from muscle spindles and golgi tendon organs. Its all for smooth motor coordination

Question 48

Describe the structure of spinocerebellar tracts

Answer 48

Has 2 neurones in the pathway. Comprises of 4 tracts that don't cross at any point

Question 49

In which spinocerebellar tracts is information from the trunk and lower limbs carried?

Answer 49

In the ventral and dorsal spinocerebellar tracts

Question 50

In which spinocerebellar tracts is information from the upper limbs carried?

Answer 50

Rostral spinocerebellar and cuneocerebellar tracts

Question 51

Where do first-order neurones from the dorsal spinocerebellar tracts synapse?

Answer 51

In the dorsal horn

Question 52

Which column do second-order spinocerebellar neurones ascend on?

Answer 52

The lateral column to the cerebellum

Question 53

Where is the lesion when someone has uncoordinated lower limb muscular activity on the same side?

Answer 53

A lesion on the same side found in the dorsal spinocerebellar tracts

Question 54

What is the corticospinal tract for?

Answer 54

For voluntary motor movement

Question 55

Describe the structure of a corticospinal tract pathway

Answer 55

A pyramidal tract formed of 2 neurones

Question 56

Where do the upper motor neurones in the corticospinal tract synapse?

Answer 56

In the ventral horn

Question 57

Where do the lower motor neurones from the corticospinal tracts synapse?

Answer 57

In the skeletal muscle

Question 58

Why are pyramidal tracts called that?

Answer 58

Because they pass through the pyramids of the medulla

Question 59

What is the pathway of pyramidal tracts from the primary motor cortex to the pyramids of the medull?

Answer 59

Primary motor cortex - internal capsule - cerebral peduncle - pons - pyramids of medulla

Question 60

What is a motor homunculus?

Answer 60

A topographic representation of the body parts and its correspondents along the precentral gyrus of the frontal lobe

Question 61

Describe what happens at the pyramids of decussation

Answer 61

Within the pyramids of the medulla, the nerve fibres decussate (cross). 80% cross the midline and become the lateral corticospinal tract. 20% remain on the same side and become the anterior corticospinal tract

Question 62

What is upper motor neurone disease?

Answer 62

The degradation of upper motor neurones that causes spastic paralysis (increased muscle tone), overactive tendon reflexes but significant muscle atrophy

Question 63

Why does upper motor neurone disease not cause muscle atrophy?

Answer 63

Because there are still lower motor neurones that provide what is needed for the muscles to survive

Question 64

What is lower motor neurone disease?

Answer 64

The degradation of lower motor neurones that causes flaccid paralysis (no muscle tone), no tendon reflexes and muscle atrophy

Question 65

What is spinal muscular atrophy?

Answer 65

A genetic condition that makes the muscles weaker and causes problems with movement.

Question 66

What is Guillain-Barre syndomre?

Answer 66

An autoimmune disorder that causes damage to the nerves, causing muscle weakness and sometimes paralysis. It involves degradation of myelin

Question 67

What is Amyotrophic lateral sclerosis?

Answer 67

A genetic disease that selectively affects lower and upper motor neurones and destroys them but keeps the mind intact. Causes a short life-span due to respiratory failure

Question 68

What are Bulbar signs?

Answer 68

Speech and swallowing difficulties associated with cranial nerves

Question 69

Where do Rubrospinal extrapyramidal tracts originate from?

Answer 69

From the red nucleus in the midbrain

Question 70

Where do Reticulospinal extrapyramidal tracts originate from?

Answer 70

From the reticular formation in the pons

Question 71

Where do Vestibulospinal extrapyramidal tracts originate from?

Answer 71

From the vestibular nuclei in the medulla

Question 72

What are extrapyramidal tracts important for?

Answer 72

For maintaining posture and regulating involuntary movements

Question 73

What are the symptoms of extrapyramidal tract lesions?

Answer 73

Movement disorders

Question 74

What is Dyskinesia?

Answer 74

Involuntary muscle movements

Question 75

What is Dystonia?

Answer 75

Involuntary muscle contractions