Get your competitive edge with Sketchy MCAT! Don't miss 15% OFF for Registration Day

Disorders of the Nervous System: Alzheimer's and Parkinson's Disease

Tags:
No items found.

Systems Biology

Alzheimer's is a neurodegenerative disease that causes memory loss and dementia, and is usually found in individuals over the age of 65. The disease is characterized by the buildup of beta-amyloid plaques and neurofibrillary tangles in the brain, and it leads to impaired neural communication and cell death. Decline of cholinergic neurons results in decreased levels of acetylcholine and impaired brain function, particularly in the hippocampus, which is responsible for memory formation. As the disease progresses, neuron loss leads to brain atrophy, flattened sulci, and enlargement of the ventricles.

On the other hand, Parkinson's disease results from the death of dopaminergic neurons in the substantia nigra, causing a decline in dopamine levels in the basal ganglia. This leads to characteristic tremors, jerky movements known as cogwheel rigidity, slowed motor responses (bradykinesia), and a stooped gait. While Parkinson's is not curable, it can be managed by administering L-DOPA, a dopamine precursor that gets converted into dopamine in the brain.

Lesson Outline

<ul> <li>Introduction: Age-related degenerative diseases of the nervous system - Alzheimer's and Parkinson's</li> <li>General symptoms and associated changes in the brain</li> <ul> <li>Alzheimer's disease <ul> <li>Typically affects people over the age of 65</li> <li>Memory loss pattern</li> <li>Dementia</li> <li>Worse symptoms in late afternoon and early evening</li> <li>Physical changes in the brain: plaques and tangles <ul> <li>Beta amyloid proteins and plaques</li> <li>Neurofibrillary tangles</li> </ul> </li> <li>Decrease in acetylcholine</li> <li>Impact on the hippocampus and memory loss</li> <li>Brain atrophy, flattened sulci, and enlargement of ventricles</li> </ul> </li> <li>Parkinson's disease <ul> <li>Death of dopaminergic neurons in the substantia nigra</li> <li>Decrease in dopamine levels in the basal ganglia</li> <li>Characteristic tremors, jerky movements, and slowed motor responses</li> <li>Stooped gait</li> <li>Treatment with L-DOPA</li> </ul> </li> </ul> </ul>

Don't stop here!

Get access to 71 more Systems Biology lessons & 8 more full MCAT courses with one subscription!

Try 7 Days Free

FAQs

What are the main differences between Alzheimer's disease and Parkinson's disease?

Alzheimer's disease is primarily characterized by memory loss and cognitive decline, whereas Parkinson's disease is mainly characterized by motor symptoms like tremors, stiffness, and balance issues. Alzheimer's disease involves the accumulation of beta-amyloid plaques and neurofibrillary tangles in the brain, while Parkinson's disease is associated with the loss of dopamine-producing neurons in the substantia nigra region of the brain.

How do beta-amyloid plaques and neurofibrillary tangles contribute to Alzheimer's disease?

Beta-amyloid plaques are abnormal protein deposits that build up between nerve cells, potentially disrupting communication between neurons and triggering inflammation. Neurofibrillary tangles are twisted protein fibers found inside neurons, composed of a protein called tau. The accumulation of these tangles can cause neurons to lose their internal structure and function, eventually leading to cell death.

What role does dopamine play in Parkinson's disease, and how do medications like L-DOPA help alleviate symptoms?

Dopamine is a neurotransmitter responsible for controlling movement, balance, and coordination. In Parkinson's disease, dopamine-producing neurons in the substantia nigra degenerate and die, leading to a decrease in dopamine levels. This results in the motor symptoms associated with the disease. L-DOPA is a precursor of dopamine that can cross the blood-brain barrier. When taken as medication, it is converted into dopamine in the brain, which can help to alleviate some of the motor symptoms in patients with Parkinson's disease.