Spinal Reflexes, UMN & Control of Movement

Question 1

Flexor Reflex

Answer 1

Noxious stimulus:
Contraction of flexor muscle via excitatory interneurones
Relaxation of extensor muscle via excitatory and inhibitory interneurones

Question 2

Crossed Extensor Reflex

Answer 2

Postural support during withdrawal of foot from painful stimulus (example):
Contraction of extensor muscles via excitatory interneurones.
Relaxation of flexor muscles via excitatory and inhibitory interneurones.

Question 3

Motor Control Heirarchy

Answer 3

Strategy (high) - neocortical association areas, basal ganglia.

Tactics (middle) - motor cortex, cerebellum

Execution (low) - brain stem, spinal cord.

Question 4

Lateral pathways

Answer 4

Under control of cerebral cortex

Voluntary control of distal musculature, skilled discrete movements (hands and fingers).

Question 5

Ventromedial pathways

Answer 5

Under control from brainstem

Important for control of posture and locomotion