05.2 Upper motor Neurones and Descending Tracts

Question 1

What can the descending motor pathways be split into?

Answer 1

Pyramidal (voluntary)

Extrapyramidal (involuntary)

Question 2

Are most descending motor neurones stimulatory or inhibitory?

Answer 2

Inhibitory

Question 3

What can pyramidal tracts be split into?

Answer 3

Corticospinal

Corticobulbar - Synapse onto cranial nerve nuclei

Question 4

Do corticospinal tracts decussate?

Answer 4

Yes

Question 5

Do corticobulbar tracts decussate?

Answer 5

Yes, some fibres do.
Facial nerve below the eyes and hypoglossal nerve are contralateral entirely.
All other cranial nerves have bilateral innervation.

Question 6

What are the extrapyramidal tracts?

Answer 6

Vestibulospinal
Reticulospinal
Rubrospinal
Tectospinal

Question 7

What does the vestibulospinal tract do?

Answer 7

Balance

Does not decussate

Question 8

What does the reticulospinal tract do?

Answer 8

Locomotion movement coordination

Bilateral innervation

Question 9

What does the rubrospinal tract do?

Answer 9

Facilitates flexor tone

Contralateral innervation

Question 10

What does the tectospinal tract do?

Answer 10

Directs head movements towards light and sound

Contralateral innervation