Neuropathology Flashcards
Give examples of glial cells.
- Astrocytes.
- Oligodendrocytes.
- Ependymal cells.
Glial cells are derived from?
Neuroectoderm.
Function of astrocytes?
Provide brain with a fixed 3D grid-structure, within which the other CNS cells are supported. Functionally, they are closely coupled with neurones.
Function of oligodendrocytes?
Wrap around axons to form myelin sheath.
Function of ependymal cells?
Line the ventricular system.
What are microglia?
Mesoderm-derived cells originating in bone marrow, serving as a fixed macrophage system.
What is hypoxia?
Anoxia (absence) or lack of oxygen.
Why does hypoxia injure CNS?
Results in energy failure of cells of the brain parenchyma.
Damage to nerve cells and/or their processes can lead to?
- Rapid necrosis with sudden acute functional failure e.g. stroke.
- Slow atrophy with gradually increasing dysfunction e.g. age-related cerebral atrophy.
When does acute neuronal injury (Red neuron) occur?
In the context of hypoxia/ischaemia.
When can acute neuronal injury be seen?
Typically visible 12-24 hours after an irreversible “insult” to the cell.
Acute neuronal injury results in what?
Neuronal cell death.
What pattern is seen in acute neuronal injury?
- Shrinking and angulation of nuclei.
- Loss of nucleus.
- Intense eosinophilia/ redness of cytoplasm.
Acute neuronal injury represents a lethal injury to the neuron typically caused by?
Ischaemia or hypoxia e.g. strokes.
What are the responses to injury/ disease of neurones?
- Acute neuronal injury.
- Axonal reactions.
- Simple neuronal atrophy (chronic degradation).
- Sub-cellular alterations (inculsions).
What is axonal reaction?
A neuronal cell body reaction associated with axonal injury.
What may be seen in an axonal reaction?
- Swelling.
- Enlarged nucleolus due to protein synthesis.
- Chromatolysis: margination and loss of Nissl granules.
- Degeneration of axon and myelin distal to site of injury: “Wallerian Degeneration”.
How do axonal reactions differ in the CNS to the PNS?
In the PNS there is often some myelin sheath preserved, thus allowing neural tube formation and some regeneration.
What can be seen in simple neuronal atrophy (chronic degeneration)?
- Shrunken, angulated and lost neurones.
- Small dark nuclei.
- Lipofuscin pigment.
- Reactive gliosis.
- Though cause dependent, often affects functionally related neurons.
Sub-cellular alterations/ inclusions to neuronal organelles and cytoskeleton are common in?
- Classically, neurofibrillary tangles in Alzheimer’s disease.
- Lewy bodies in Lewy Body Dementia and Parkinson’s.
- Neural inclusions in ageing.
- Intranuclear and cytoplasmic inclusions in viral disease.
Simple neuronal atrophy occurs in diseases of long duration, for example?
- MS.
- Alzheimer’s.
Neurofibrillary tangles are classically associated with which disease?
Alzheimer’s.
Lewy bodies are associated with which diseases?
Lewy body dementia and Parkinson’s.
Neural inclusions appear to accumulate with?
Ageing.