Q.What is Parkinson's disease? Name the neurotransmitter whose deficiency is associated with it and state two common symptoms.

[!TLDR] Parkinson's disease results from loss of dopamine-producing neurons in the substantia nigra of the midbrain; symptoms include resting tremor and muscle rigidity (also bradykinesia and postural instability). [!ANSWER] Neurotransmitter deficient: dopamine. Symptoms: resting tremor and muscle rigidity (also bradykinesia, postural instability).

Parkinson's disease is a progressive disorder of the nervous system caused by the degeneration of a specific group of neurons in the substantia nigra, a region of the midbrain; these neurons normally produce the neurotransmitter dopamine, which is essential for the smooth initiation and control of voluntary movement, so as they are progressively lost, brain dopamine levels fall. The characteristic symptoms are predominantly motor: a resting tremor (rhythmic shaking, often most noticeable in the hands when at rest), muscular rigidity (increased stiffness and resistance in the muscles), along with bradykinesia (slowness of movement) and postural instability. There is no cure, but symptoms can often be managed for some years with dopamine-related medication. [!ANSWER] Dopamine deficiency (from loss of substantia-nigra neurons in the midbrain) causes Parkinson's disease; its common symptoms include resting tremor and muscular rigidity.

Link the specific neurotransmitter (dopamine) and brain region (substantia nigra, midbrain) to the resulting motor symptoms.

Do not attribute Parkinson's disease to a memory-protein cause — that describes Alzheimer's disease; Parkinson's is specifically a dopamine/movement disorder.