Staged Effects on the brain

From the simple introduction of alzheimer's disease and where the name originated from I was curious as the effect the disease has on the brain. Alzheimer discovered and coined the terms "amyloid plaques" and "neurofibrillary tangles" but what are those? and What do each of them do to the brain as the disease progresses?

Amyloid plaques are abnormal clumps in the brain. These particular plaque deposits are found in spaces between the brain’s nerve cells. The plaques consist of large deposits of a toxic protein called beta-amyloid. Many people develop some plaques as they age, but it is unsure if these plaques are side effects of Alzheimer’s or a major cause of the disease.

“Neurofibrillary tangles are abnormal collections of twisted protein threads found inside nerve cells.” The effect of the major component of the tangles which is a protein called tau causes the microtubules in the brain to disintegrate in turn the “internal transport network will collapse. This collapse stops the ability of neurons to communicate.

Which leads to the third effect of AD, the loss of connections between neurons in the brain. The loss of neuron communication can eventually lead to death of many neurons as well as further shrinking of the affected areas. The shrinking of the brain is known as brain atrophy.