How Does Alzheimer's Affect the Brain?
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What is Alzheimer's Disease?
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Alzheimer's disease is the most common form of dementia. Dementia is a disorder of the brain that impairs how it functions and limits a person's effectiveness at performing normal activities of daily living. It is unknown what causes Alzheimer's disease, and there is no known cure. It is a progressive disease that begins with mild symptoms of forgetfulness. It eventually results in death. The progression of the disease can be slowed, and people can live from eight to twenty years after diagnosis. It is estimated that over four million people in the United States have Alzheimer's disease, which usually sets in after age sixty.
The Brain at the Beginning Stages of Alzheimer's Disease
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Alzheimer's symptoms may first show up as memory loss or difficulty performing every day thinking tasks such as simple math problems. This is due to the death of nerve cells in the brain that work in the memory center. The ability of these cells to communicate with the rest of the nervous system is impaired. Some of the physiological telltale signs of Alzheimer's are the formation of clumps in brain called amyloid plaques, as well as tangled nerve fibers called neurofibrillary tangles.
Brain Functioning in the End Stages of Alzheimer's Disease
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As Alzheimer's progresses, symptoms of memory loss and changes in mood and behavior become more than just a nuisance and start to affect the normal activities of daily living. As the degeneration of the brain progresses, people forget how to do simple things like hair-brushing and they may forget the names of the people they know very well.
Since some of the symptoms of Alzheimer's can be similar to other diseases and conditions such as brain tumors or depression, doctor's conduct a series of tests to rule out possible causes in an attempt to make a correct diagnosis. These tests may include asking questions about symptoms and behavior and conducting brain scans.
Currently, the only way to see the physiological changes in the brain is by conducting an autopsy after death, but studies are being done to find out whether the clumps and tangles can be seen with an MRI (magnetic resonance imaging).
Inside the Brain of Someone With Alzheimer's
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If you could open your head to see an touch your brain, it would feel firm but jelly-like. It weighs about three pounds and is made up of the cerebrum (front), cerebellum (back) and the brain stem. Each part of the brain has a specific function, be it for memory, sight, smell, breathing and every other function humans carry out with or without being aware of it. The brain is made of billions of nerve cells called neurons. These cells are destroyed by Alzheimer's disease. The brain works by the communication of neurons with each other to carry information. Neurons communicate by sending and receiving a small electrical charge and tiny molecules of chemicals called neurotransmitters. Alzheimer's affects this communication by disturbing the electrical charge and the neurotransmitters.
Alzheimer's causes neurons to die which causes the brain to shrink. This leads to a loss of functioning capabilities in almost all parts of brain, not just the ones that affect memory. This leads to the formation of clumps and tangles within the brain and eventually death.
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