Parkinson's disease is caused by

Appeared in: IGNOU PB Bsc Entrance-2022

Explanation

Parkinson's disease is a neurodegenerative disorder characterized by a loss of dopamine-producing (dopaminergic) neurons.
These specific neurons are located in the substantia nigra, a critical component of the basal ganglia.
The basal ganglia are a group of structures deep within the brain responsible for controlling voluntary motor movements.
The resulting dopamine deficiency disrupts the brain's motor control circuits, leading to symptoms like tremor, rigidity, and bradykinesia (slowness of movement).

Option A: This describes the pathophysiology of Multiple Sclerosis (MS), an autoimmune disorder affecting the central nervous system.
Option B: The corpora quadrigemina are reflex centers for vision and hearing. Their breakdown is not the primary cause of Parkinson's disease.
Option C: This is the underlying mechanism of Myasthenia Gravis, an autoimmune disorder affecting the neuromuscular junction.

Clinical Relevance

Nursing practice connection: Knowing Pathophysiology of Parkinson's Disease helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must administer antiparkinsonian medications like Levodopa strictly on schedule to maintain therapeutic dopamine levels and prevent 'off' periods where symptoms worsen.
Patient safety is a top priority. Due to postural instability and a shuffling gait, nurses must implement fall precautions, such as ensuring a clutter-free environment and using assistive devices.
What if? If a patient with Parkinson's disease develops sudden confusion and visual hallucinations, the nurse should first assess for other causes like infection (e.g., UTI) or medication side effects, rather than assuming it's just disease progression, and report findings promptly.

How to Approach the Question

First, identify the keywords in the question stem: 'Parkinson's disease' and 'caused by'. This indicates the question is asking for the fundamental pathophysiology.
Next, recall the core pathology of major neurological disorders. Parkinson's is famously associated with a specific neurotransmitter and brain region.
Evaluate each option. Option A (myelin sheath) points to Multiple Sclerosis. Option C (acetylcholine receptors) points to Myasthenia Gravis.
Option B (corpora quadrigemini) relates to sensory reflexes, not the primary motor deficits of Parkinson's.
Option D correctly links the disease to the degeneration of neurons in the basal ganglia, which is the known cause due to dopamine loss in the substantia nigra.

Concept Tested & Keywords

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 1280-1282

E6 Pharmacology Katzung 16e p. 771-773

E6 Medicine Davidson Principles Practice 24e p. 1132-1134

Practise the full IGNOU PB Bsc Entrance-2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.