Alzheimer's Disease
A type of dementia characterised by the gradual widespread degeneration of brain neurons, progressively causing memory decline, deterioration of cognitive and social skills and personality changes. Short term memory loss is the first to go, followed by long- memory. In the initial stage, deficits are evident in a number of areas but the person can function. Later they may forget, events, words, directions, knowledge and everyday skills. In a brain with Alzheimer's there is a high level of abnormal structures that interfere with neural communication within and between neurons, and therefore cognitive functioning. These abnormalities involve plaques and tangles.
Plaques
Fragments of the protein beta amyloid, and in a healthy brain that protein is broken down and eliminated. In a brain with Alzheimer's the fragments accumulate over time, and form insoluble clumps outside and around neurons, therefore inhibiting neural communication.
Tangles
Neurofibrillary tangles look like twisted fibres, and inhibit transport of essential substances through the neurons, this is thought to kill the neurons.