Alzheimer's disease
Two of the main features found in the brains of people with of Alzheimer's disease, are neurobrillary tangles ('tangles' for short), which are made up of a protein called tau, and senile plaques (which are made mostly from another protein called beta-amyloid, they are also sometimes called beta-amyloid bundles or 'bundles' for short). The tau proteins that form the tangles previously held together a structure inside the neurons called a microtubule which is an important part of the neuron; it forms part of the cytoskeleton (cell skeleton) which is what maintains a cell's shape, and microtubules plays a part in cell communication.