4.0 neuro - motor systems

Question 1

What parts of the central and peripheral motor cortex are involved with motor behaviors

Answer 1

motor cortex, basal nuclei, cerebellum, brain stem, spinal cord, cranial nerves, spinal/peripheral nerves

Question 2

What is an upper motor neuron and where are they

Answer 2

in the motor cortex, travel down the brain stem and spinal cord, initiate movement

Question 3

What is a lower motor neuron and where are they

Answer 3

spinal cord, connect to skeletal muscle

Question 4

What part of the spinal cord is motor

Answer 4

ventral

Question 5

What part of the spinal cord is sensory

Answer 5

dorsal

Question 6

List all parts of the direct motor pathway in the correct order

Answer 6

• motor cortex
• subcortical white matter
• internal capsule
• crus cerebri (midbrain)
• basal pons (pons)
• pyramids (medulla oblongata)
• corticospinal tracts: lateral and ventral (spinal cord)
• spinal cord ventral horn
• ventral roots
• peripheral nerves
• skeletal muscle

Question 7

Where do direct motor fibers in the lateral corticospinal tract decussate (cross the midline)

Answer 7

at the pyramidal decussation

Question 8

Where do direct motor fibers in the ventral corticospinal tract decussate (cross the midline)

Answer 8

most in the spinal cord, some do not cross

Question 9

What fibers travel in genu of the internal capsule

Answer 9

motor axons for the brain stem, corticonuclear tracts which contain fibers that control the skeletal muscles of the head and neck

Question 10

What fibers travel in the posterior limb of the internal capsule

Answer 10

motor axons for the trunk and extremities

Question 11

What is the primary motor area of the cerebral cortex responsible for

Answer 11

Initiation of voluntary movements

Question 12

Where are voluntary movements initiated

Answer 12

the primary motor area of the cerebral cortex, area 4, precentral gyrus

Question 13

What step in the motor pathway happens in the premotor cortex

Answer 13

thinking about movement

Question 14

What step in the motor pathways happens in the precentral gyrus

Answer 14

initiating movement (upper motor neurons)

Question 15

What are corticonuclear tracts

Answer 15

white matter pathways that carry motor information from the motor cortex to skeletal muscles of head and neck to coordinate precise, voluntary movements

Question 16

What does the internal capsule continue as

Answer 16

crus cerebri

Question 17

Where is the crus cerebri located

Answer 17

at the base of the midbrain

Question 18

What is the pyramidal decussation

Answer 18

defines the border between the spinal cord and medulla oblongata, where the pyramidal tracts cross the midline

Question 19

The axons from the corticonuclear spinal tract synpase on the nuclei of which cranial nerves

Answer 19

CN V, VII, IX, XII

Question 20

What are the two corticospinal tracts

Answer 20

lateral and ventral

Question 21

What is the difference between the fibers in the lateral and ventral corticospinal tracts

Answer 21

lateral: fibers crossed the midline at the pymidal decussation
ventral: fibers did not cross at pyramidal decussation, most fibers do cross in the spinal cord

Question 22

what do fibers of the lateral corticospinal tract innervate

Answer 22

skeletal muscles on the opposite side of the body, arms and legs

Question 23

what do fibers of the ventral corticospinal tract innervate

Answer 23

skeletal muscles on both sides of the body, trunk movements

Question 24

where do corticospinal tracts synpase

Answer 24

ventral horn