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5 Cards in this Set
- Front
- Back
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six areas suffering greatest neuron loss in Alzheimer's
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a. Neo-cortex; mostly "association areas", Area 28 or the entorhinal cortex
b. Hippocampus c. Amygdala;limbic system area involved in "learned fear" and other emotional behavior d. Nucleus basalis of Meynert, in "substantia innominata"; so small that it cannot be seen easily on sections of the brain stained with cell stains; located at about the same level as, and inferior to, the lentiform nucleus; projects directly to cortex--not thru thalamus e. Nucleus locus coeruleus ("blue spot"); tiny nucleus in the pontine reticular formation; neurons contain the pigment melanin (giving them a dark or bluish appearance in the fresh brain); important for vascular regulation and selective attention; sleep regulation f. Raphe nuclei; a column of neuronal groups in the midline of medulla, pons, and midbrain reticular formation (with names like “nucleus obscurus”) which use 5HT as a neurotransmitter; widespread neocortical projections, especially to frontal lobe (without a relay in the thalamus), and to other structures such as the hippocampus |
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Changes in neuron cell bodies in Alzheimer's disease
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1 decreased staining of neurons in general w/ Nissle stains
2 if stained with a silver stain neurofibrillary tangles can be identified in neuronal cell bodies |
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Changes in dendritic shafts and spines in Alzheimer's
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decrease in dendritic branches and spines, particularly of neurons in the main affected areas (Golgi method);
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4 biochemical changes in alzheimer's also occur due primarily to the degeneration of particular groups of neurons
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1. Decreases in ACh and its synthetic and degradative enzymes; due to the degeneration of nucleus basalis of Meynert and to the destruction of interneurons (Golgi Type II small integrative cells)
2. Decreases in NE in the cortexdue to the degeneration of the nucleus locus coeruleus 3. Decreases in 5HT or serotonin are due to degenerative changes in raphe nuclei 4. Decreases in somatostatin (a putative neuropeptide neurotransmitter or neuromodulator); degeneration of cortical neurons contributing to long association pathways |
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summary of 6 major changes in brain w/ Alzheimers
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• Degeneration of neocortical "association" or "higher order" areas
• Degeneration of the hippocampus, amygdala, other limbic system areas • Degeneration of reticular formation nuclei, including the nucleus basalis of Meynert, nucleus locus coeruleus, and raphe nuclei • Degeneration of long association fiber pathways • Degeneration of integrative interneurons • There is also the accumulation in the brain and blood vessels of amyloid; the blood-brain barrier may also be compromised |
