Alzheimer's (pathology)

Question 1

Macroscopic changes seen in Alzheimer’s include:-

Answer 1

Hippocampal atrophy
Cerebral atrophy
Low brain weight
Enlargement of the inferior horn of the lateral ventricle

Question 2

Microscopic changes seen in Alzheimer’s include:-

Answer 2

Senile plaques (extracellular deposits of beta amyloid in the gray matter of the brain)
Neurofibrillary tangles (intracellular composition of tau protein)
Gliosis
Degeneration of the nucleus of Meynert
Hirano bodies

These changes tend to occur in the cortex but also occur in the subcortical areas.

Neurofibrillary tangles consist of hyperphosphorylated tau and plaques consist of a peptide called amyloid-beta, which is derived from amyloid precursor protein.

Question 3

Degeneration of which of the following structure is thought to lead to the loss of cholinergic innervation seen in Alzheimer’s?

Answer 3

The nucleus of Meynert has been established as the main source of acetylcholine in the brain. It is found to be atrophic in Alzheimer’s thus explaining both the loss of acetylcholine in this condition and the success of cholinesterase inhibitors.
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