Descending pathways

Question 1

What are the two categories of the descending pathways?

Answer 1

Lateral and medial

Question 2

Where are the lateral pathways found?

Answer 2

Lateral part of the ventral horn

Question 3

Where are the medial pathways found?

Answer 3

Medial part of the ventral horn

Question 4

What does the lateral pathway control?

Answer 4

Distal parts of the body; lateral musculature

Question 5

What does the medial pathway control?

Answer 5

Proximal parts of the body; medial musculature

Question 6

What are the two tracts of the lateral pathway?

Answer 6

Corticospinal and rubrospinal

Question 7

Where does the corticospinal tract originate from?

Answer 7

Primary motor, premotor, and somatosensory cortexes

Question 8

What does the corticospinal tract control?

Answer 8

Very distal movements (e.g. hands and fingers)

Question 9

What are hatchings?

Answer 9

Terminations of corticospinal fibres; synapses where corticospinal fibres connect directly to motor neurones in ventral horn

Question 10

What is the implication of having more hatchings?

Answer 10

Have finer distal control

Question 11

Where does the rubrospinal tract originate from?

Answer 11

Red nucleus in midbrain

Question 12

Why is the red nucleus named so?

Answer 12

Is very vascular

Question 13

Where does the rubrospinal tract receive information from?

Answer 13

Cerebellum + primary motor cortex

Question 14

What does the rubrospinal tract control?

Answer 14

Fore- and hind-limbs, as fibres terminate primarily at cervical and lumbar enlargements of the cord

Question 15

If the corticospinal tract is injured, what happens?

Answer 15

Rubrospinal tract compensates almost completely, but cannot compensate for individual control of digits; fingers can only be used together

Question 16

Why does the left brain control the right body?

Answer 16

Corticospinal tracts cross over at medulla, whilst rurospinal tracts cross immediately after leaving red nucleus

Question 17

What are the two tracts of the medial pathway?

Answer 17

Vestibulospinal and reticulospinal

Question 18

Where does the vestibulospinal tract originate from?

Answer 18

Vestibular nuceli

Question 19

Where does the output from the vestibulospinal tract go?

Answer 19

Spinal cord and muscles that move the eyes

Question 20

What does the vestibulospinal tract control?

Answer 20

Coordinates movement with balance when body is moved; provides sense of balance and spatial orientation

Question 21

Where does the reticulospinal tract originate from?

Answer 21

A set of interconnected nuclei throughout brainstem; reticular formation

Question 22

What does the reticulospinal tract control?

Answer 22

Maintains tone, balance and posture; predicts postural consequences of planned (volitional) movements