Chapter 9 - Spinal Cord, Brainstem, and Cortex Control of Motor Function

Question 1

What are the neurotransmitters used by UMNs and LMNs?

RL9 S4

Answer 1

UMN:
-glutamate

LMN:
-acetylcholine

Question 2

What types of nerves are cranial nerves?

RL9 S4

Answer 2

LMNs

Question 4

What sensory fiber type do nociceptors and thermoreceptors belong to?

RL9 S5

Answer 4

C fibers or A-δ fibers

Question 5

What is the function of muscle spindles and what fiber types are present?

RL9 S6-7

Answer 5

Sensory, non-contractile fibers that detect changes in muscle length. In parallel with extrafusal fibers.

Triggers stretch reflex which causes muscle to contract.

Signal through gamma motor neurons.

Nuclear bag fiber:
-detects rate of change

Nuclear chain fiber:
-detects static change

Question 6

What is the Golgi tendon organ and its function?

RL9 S11

Answer 6

Sensory organ in muscle tendon fibers. In series with extrafusal fibers.

Stimulated by stretching and results in inhibition of muscle contraction

Question 7

What is the flexor and crossed extensor reflex?

RL9 S12

Answer 7

Flexor reflex:
-flexion of ipsilateral extremity in response to painful stimulus

Crossed extensor reflex:
-extension of contralateral extremity response to painful stimulus

Question 8

What is the function of the premotor and supplementary motor areas?

RL9 S13

Answer 8

Generate plan for movement and transfers plan to primary motor cortex.

Question 9

What are the classifications of UMN and what is their functions?

RL9 S14

Answer 9

Medial activation system:
-innervates postural and girdle muscles

Lateral activation system:
-innervates distal muscles

Nonspecific activation system:
-reflex arcs