Plaques and Tangles of Alzheimers disease:
One of the hallmarks of Alzheimer's disease is the accumulation of
amyloid plaques between nerve cells (neurons) in the brain. Amyloid is a
general term for protein fragments that the body produces normally.
Beta amyloid is a protein fragment snipped from an amyloid precursor
protein (APP). In a healthy brain, these protein fragments are broken down and eliminated. In Alzheimer's disease, the fragments accumulate to form hard, insoluble plaques.
Neurofibrillary tangles are insoluble twisted fibers found inside the
brain's cells. These tangles consist primarily of a protein called tau,
which forms part of a structure called a microtubule. The microtubule
helps transport nutrients and other important substances from one part
of the nerve cell to another. In Alzheimer's disease, however, the tau
protein is abnormal and the microtubule structures collapse.
Source: American Health Assistance Foundation