Voluntary Movements

Question 1

What are voluntary movements?

Answer 1

• Self initiated
• Purposeful to achieve/do something
• Learned
• Improved with practice
• Adaptable

Question 2

What is a central pattern generator (CPG)?

Answer 2

Neuronal circuit which can produce RHYTHMIC motor patterns such as walking, breathing in the ABSENCE of sensory inputs

Question 3

What is the corticobulbar pathway?

Answer 3

2 Neuron path connecting cerebral cortex with the cranial nerve nuclei in the brainstem involved in MOTOR functions (apart from OCULOMOTOR NERVE)

Question 4

What cranial nerves are innervated by the corticobulbar tract/pathway?
remember motor only

Answer 4

• Trigeminal CN-V; muscles of mastication
• Facial CN-VII; muscles of facial expression
• Vagus CN-X; soft palate, pharynx, larynx
• Hypoglossal CN-XII; extrinsic muscles of tongue

Question 5

What is a descending pathway?

Answer 5

A motor pathway going down the spinal cord

Question 6

What happens when there is damage to descending pathways?

Answer 6

Impairs normal function causing paralysis (palsy). Nature of palsy/paralysis depends on the extent of the damage

Question 7

What happens when paralysis of Lower Motor Neurons?

Answer 7

• Final common pathway
• Nerve injury, can be viral infection (polio)
• No reflexes
• No voluntary movement
• Results in muscle atrophy

Question 8

What happens when paralysis of Upper Motor neurons?

Answer 8

• Cortico-spinal tract
• Cortico-bulbar
• CNS injury, such as from a stroke
• No voluntary involvement
• Reflexes present but exaggerated

Question 9

What is Parkinson’s disease?

Answer 9

• Hypokinetic disorder (decreased movements)
• Difficulty imitating movements
• Dopamine deficiency in substantia nigra (located midbrain)

Question 10

What is Huntington’s disease?

Answer 10

• Hyperkinetic disorder (increased movements)
• Excessive movements
• Due to imbalance of neurotransmitters

Question 11

What is the function of cerebellum in movement?

Answer 11

• Important in co-ordinating movements
• Regulates actions of antagonistic muscle groups (quad and hamstrings for example)
• Important in maintaining balance

Question 12

How can you diagnose cerebellar disorders? (faulty cerebellum)

Answer 12

• Characterised by loss of coordination
• Imprecise actions
• Inability to coordinate alternating contractions of antagonistic muscles (biceps vs triceps example)