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PATHOPHYSIOLOGY. Classic Neuropathologic Findings:. Amyloid Plaques. - dense, insoluble deposits of amyloid -beta proteins, which are fragments of amyloid precursor proteins (APP), a transmembrane neuronal protein. . Neurofibrillary Tangles.
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Amyloid Plaques • - dense, insoluble deposits of amyloid-beta proteins, which are fragments of amyloid precursor proteins (APP), a transmembrane neuronal protein.
Neurofibrillary Tangles • paired helical filaments composed of tau proteins • essential for axonal growth and development • when hyperphosphorylated, the tau proteins form tangles • these tangles break down the neurons' ability to transport molecules along the axon • - these are then deposited within neurons located in the hippocampus, medial temporal lobe, parieto temporal region and the frontal association cortices leading to cell death.
Synaptic and Neuronal Cell Death Death of cholinergic neurons in the basalis nucleus of Meynert - leads to a deficit in Acetylcholine (major transmitter in memory) Serotonergic neurons in median raphe and adrenergic neuron in locus ceruleus - leads to deficits in serotonin and norepinephrine, respectively