Motor System

Question 1

UMN

Answer 1

arise in the cerebral cortex/brainstem and their axons travel in descending tracts to synapse with LMNs and/or interneurons

Question 2

LMN

Answer 2

cell bodies are located in the SC/brainstem and synapse with skeletal muscle fibers

Question 3

Cerebellum

Answer 3

• pathways used to adjust movements and posture
• balance and coordination
• motor planning

Question 4

Basal ganglia

Answer 4

regulates:
- muscle contractions
- muscle force
- multi-joint movements
- sequence of movements

Question 5

What is the common motor pathway?

Answer 5

Corticospinal pathway:

• direct connection between the cerebral cortex and the spinal cord
• synapses with LMN that control the neck, shoulder, and trunk muscles

Question 6

UMN lesions (6)

Answer 6

• spasticity, velocity dependent
• hypertonia
• paresis and paralysis
• abnormal reflexes
• loss of fractionation movement
• abnormal timing of muscle activity

Question 7

LMN lesions (5)

Answer 7

• rigidity, velocity dependent
• flaccidity
• loss of reflexes
• atrophy
• fibrillations