Final answer:
Parkinson's disease is a neurodegenerative disease caused by a decrease of dopamine. It is characterized by the loss of dopamine neurons in the substantia nigra and leads to symptoms such as tremor, slowed movement, speech changes, balance and posture problems, and rigid muscles.
Step-by-step explanation:
Parkinson's disease is a neurodegenerative disease caused by a decrease of dopamine. It is characterized by the loss of dopamine neurons in the substantia nigra, a midbrain structure that regulates movement. This loss of dopamine neurons leads to symptoms such as tremor, slowed movement, speech changes, balance and posture problems, and rigid muscles.
Some relevant information about Parkinson's disease includes:
* It was first characterized by James Parkinson in 1817.
* Each year, 50,000-60,000 people in the United States are diagnosed with the disease.
* Parkinson's disease can also exhibit psychological symptoms, such as dementia or emotional problems.