Alzheimer's Disease and Dementia Flashcards
What is Alzheimer’s Disease and Dementia?
It is a chronic degenerative brain disorder related to aging.
Minor forgetfulness -> Major memory disruptions -> Generalized dementia -> Widespread psychological dysfunction -> Death.
Alzheimer’s causes how much of all Dementia?
60-70%.
When can you get a true diagnosis of AD?
Post-mortem.
How many Canadians are affected by AD?
Over 500,000 (and an additional 25,000 cases diagnosed every year).
How many Canadians are expected to be affected by Alzheimer’s Disease in 2031?
937,000 Canadians (this is a 66% increase).
What are the early clinical symptoms of AD?
Short-term memory loss.
Subtle problems with executive function.
Apathy.
What are the late clinical symptoms of AD?
Difficulty with language.
Disoriented.
Mood swings.
What are the advanced clinical symptoms of AD?
Loss of motivation.
Loss of bodily functions.
Dependent on caregivers.
What causes AD?
Genetics (70%) Exposure to environmental elements Immune reactions Slow viruses Prions (abnormal, infectious forms of proteins)
What are the two principle neuronal changes that occur in AD patients?
Loss of cholinergic cells in the basal forebrain.
Development of neurotic plaques and tangles in the cerebral cortex.
Is there a cure for AD?
No.
What is ACh?
Acetylcholine is among the first neurotransmitters ever discovered.
Where is the ACh located?
It is widely distributed throughout the brain.
ACh plays a crucial role in what branches of the Autonomic Nervous System?
Sympathetic and Parasympathetic.
Note that it also plays a crucial role in the CNS
ACh is responsible for what? Due to its release where?
It is responsible for muscle contractions, as it is released at Neuromuscular Junctions.
Where are Cholinergic cell bodies located?
Basal Forebrain - they project to the hippocampus and cortex.
Midbrain - projects to the Basal Ganglia, Thalamus, Diencephalon, Pons, Cerebellum, Cranial Nerve Nuclei, and Reticular Formation.
ACh neurons in the Basal Forebrain are involved in what?
Cognitive function, particularly learning and memory.
How do drugs enhance memory?
They increase activity of the ACh.
Cells in what anatomical brain region are the first to die in AD?
Basal Forebrain - specifically in he Entorhinal Cortex.
How does Neurodegeneration spread?
It spreads outwards and extends into the cerebral cortex, as disease progresses.
What are the main pathological features of AD?
Plaques and Neurofibrillary Tangles.
What do Plaques and Neurofibrillary Tangles do?
They interfere with normal processing of action potentials and cellular functions.
Decrease in inter-neuronal associations - and as they become more and more “choked off” from their circuits, they begin to die.
What are Neuritic Plaques composed of?
A central core of homogenous proteins called B-Amyloid.
What is B-Amyloid?
It is a product of the Amyloid Precursor Gene.
It is involved in the activation of kinases, protection against oxidative stress, regulation of cholesterol transport, etc.
Where are the plaques located?
They are concentrated in the Temporal Lobe areas involved in memory.
What are Neurofibrillary Tangles?
They are paired helical filaments found in the Cerebral Cortex and Hippocampus.
What is Cytoskeleton?
It is the evolutionary solution to maintaining a neuron’s 3D structure.
It functions as both flexible scaffold and transportation system.
What are neurons?
3-Dimensional creatures that require structural support.
What are the three main components to the Cytoskeleton?
Neurofilaments
Microtubules
Microfilaments
What are Neurofilaments?
Control and transport the membrane proteins.
What are Microtubules?
Control the transfer/movement of substances and organelles throughout the cytoplasm.
What are Microfilaments?
Provide structural support to axons and dendrites.
What are TAU proteins?
They are involved in the stabilization and flexibility of microtubules and microfilaments.
They are a highly soluble protein.
Activated through phosphorylation.
Promote the assembly of microtubules.
When Hyperphosphorylated TAU proteins aggregate, what do they form?
Neurofibrillary Tangles.
