Descending Spinal Tracts

Question 1

Upper motor neurons regulate the ___________________ side of the body

Answer 1

CONTRALATERAL

Question 2

Motor fibers decussate along their path to the __________________.

Answer 2

spinal cord

Question 3

Lower motor neurons regulate the ___________________ side of the body

Answer 3

IPSILATERAL

Question 4

_________________ corticospinal tract regulates the movement of muscles of the trunk

Answer 4

Anterior

Question 5

________________ corticospinal tract controls movement of upper and lower limbs

Answer 5

Lateral

Question 6

Which descending tract is not present in the spinal cord?

Answer 6

Corticobulbar

Question 7

Which descending tract exits in the brainstem at cranial nerve nuclei and regulates movement of the face, jaw, tongue, and throat?

Answer 7

Corticobulbar

Question 8

The corticobulbar tract regulated movement in what four parts of the body?

Answer 8

1. face
2. jaw
3. tongue
4. throat

Question 9

TRUE or FALSE:
Corticospinal tracts involve voluntary muscle movement of upper and lower limbs.

Answer 9

TRUE

Question 10

Upper motor neurons (UMNs) from the motor cortex descend in thick tracts through the ________________ and then form the _______________.

Answer 10

internal capsule
pyramids

Question 11

85% of the corticospinal tract fibers decussate at the _____________ and form the __________________.

Answer 11

caudal medulla
lateral corticospinal tract

Question 12

15% of remaining corticospinal tract fibers descend _____________ and form the ______________________.

Answer 12

ipsilaterally
anterior corticospinal tract

Question 13

Lateral corticospinal tract (85% of fibers, decussated at the medulla) controls _______________.

Answer 13

movement of limbs

Question 14

Anterior corticospinal tract (15% of fibers, ipsilateral) controls ________________________.

Answer 14

muscles of the trunk

Question 15

Fibers from the ___________ corticospinal tract decussate at the spinal cord level where they exit.

Answer 15

anterior

Question 16

Lateral corticospinal decussate at the _______________.

Answer 16

medulla

Question 17

Anterior corticospinal decussate at the _______________.

Answer 17

spinal cord

Question 18

The ________________ allocates a region for movement of each part of the body.

Answer 18

motor cortex

Question 19

In regards to the somatotopic distribution, the corticospinal fibers descend throughout the _________________.

Answer 19

spinal cord

Question 20

The corticospinal fibers descend organized through the __________________________.

Answer 20

internal capsule

Question 21

The lower motor neuron innervate are ____________________________ organized as well.

Answer 21

somatotopically

Question 22

With the corticobulbar tract, ___MNs from the motor cortex descend and synapse with cranial nerve nuclei. What are the cranial nerves associated with this?

Answer 22

UMNs

1.) Trigeminal (CN V)
2.) Facial (CN VII)
3.) Hypoglossal (CN XII) [also nucleus ambiguous for CN IX & x)

Question 23

How does motor nucleus of trigeminal nerve impact the body?

Answer 23

Muscles of mastication

Question 24

How does motor nucleus of facial nerve impact the body?

Answer 24

Muscles of facial expression

Question 25

How does motor nucleus of IX and X, and hypoglossal XII impact the body?

Answer 25

Muscles of the palate, pharynx, tongue, and larynx

Question 26

UMNs in motor cortex –> LMNs

Answer 26

1. motor nucleus in CN v (PONS)
2. facial nucleus VII (PONS)
3. nucleus ambiguous IX, X (MEDULLA)
4. hypoglossal nucleus XII (MEDULLA)