Mechanisms of Spasticity and Baclofen [Biochemical & Macroscopic]

The video tutorial explains the role of calcium in neurotransmitter exocytosis at the axon terminal, focusing on glutamate and substance P. It discusses the function of GABA B receptors and the effects of baclofen in treating spasticity by inhibiting calcium influx and facilitating potassium efflux. The tutorial also covers motor neuron pathways, the concept of spasticity, and the stretch reflex mechanism. Baclofen's role in reducing spasticity and its impact on muscle control is highlighted.

What is the primary role of calcium at the axon terminal?

• To block voltage gated channels

• To trigger exocytosis of neurotransmitters

• To decrease axoplasmic concentration

• To inhibit neurotransmitter release

Which neurotransmitter is primarily excitatory?

• GABA

• Dopamine

• Serotonin

• Glutamate

What effect does baclofen have on GABA B receptors?

• It inhibits them

• It activates them

• It has no effect

• It destroys them

What happens when the inhibitory subunit binds to voltage gated calcium channels?

• Calcium influx is increased

• Calcium influx is inhibited

• Potassium efflux is decreased

• Neurotransmitter release is enhanced

What is the default state of lower motor neurons?

• Neutral

• Hyperpolarization

• Excitation

• Inhibition

What is the term for releasing inhibition on a lower motor neuron?

• Depolarization

• Excitation

• Hyperpolarization

• Disinhibition

What is the role of muscle spindles in the stretch reflex?

• To block nerve signals

• To detect muscle stretch

• To enhance muscle relaxation

• To inhibit muscle contraction

What happens to the stretch reflex when upper motor neurons are damaged?

• It is inhibited

• It becomes exaggerated

• It remains unchanged

• It is completely blocked

How does baclofen help in managing spasticity?

• By blocking all nerve signals

• By enhancing muscle contraction

• By inhibiting the 1a afferent neuron

• By increasing excitatory input

Why is flexor synergy more common in upper motor neuron lesions?

• Flexors are less affected by spasticity

• Extensors are more spastic

• Flexors produce more force than extensors

• Flexors are unaffected by cerebral insults