Question

Degeneration of the neurons in which of the following structures leads to the muscle tremors associated with Parkinson disease?

1. Cerebral crus
2. Tegmentum
3. Pons
4. Substantia nigra
5. Inferior colliculi

Answer 1

Degeneration of neurons in the substantia nigra leads to muscle tremors associated with Parkinson's disease due to the loss of dopamine required for movement regulation.

Step-by-step explanation:

The muscle tremors associated with Parkinson disease are caused by the degeneration of neurons in the substantia nigra, which is a structure within the basal nuclei of the brain. The substantia nigra has an important role in regulating movements by releasing dopamine into the striatum. Dopaminergic neurons in this region are particularly vulnerable to damage due to factors like mitochondrial dysfunction, oxidative stress, and glutamate excitotoxicity, leading to the characteristic motor symptoms of Parkinson's disease, such as tremors and rigidity.