Lucy's Pathology Flashcards
How many types of primary neuronal damage?
2 main types
What are the 2 main types of primary neuronal damage?
RAPID NECROSIS
SLOW ATROPHIC CHANGE
What is associate with rapid necrosis?
Hypoxia
- Nuclear pyknosis
- Cytoplasmic shrinkage
What is nuclear pyknosis?
Irreversible condensation of chromatin in nucleus
What is slow atrophic change assoc with?
Gradual loss of function (dementia)
-Cells slowly become smaller and eventual dissolution
Note about destruction of neurones?
No regeneration of destroyed neurons
Explain colloquially difference between the 2 types of primary neuronal damage?
Rapid necrosis: No time for cell to become smaller, suddenly damaged so nucleus and cytoplasm die
Slow atrophic change: Neuron is gradually dying so it becomes smaller as it dies
Explain secondary neuronal damage?
Neuronal damage isn’t main event but occurs due to something else being damaged
2 types of secondary neuronal damage?
Retrograde degeneration
Trans-synaptic degeneration
What is retrograde degenration?
When main axon is damaged there is degeneration of neuron as well as classical distal degeneration of axon
Cell becomes swollen and there is loss of Nissl substance
What is more susceptible to damage astrocytes or neurons?
Neurons
Describe process of gliosis?
Sufficient damage, astrocytes multiply and enlarge, there is an increase in fibril formation
-Later cells atrophy leaving dense meshwork of fibres, creating the analogue to scar tissue
What can help you recognise gliosis in histological sections? and how?
GFAP: Cells and fibres contain this
Using antibodies to find
What gathers round neurons when they are damaged?
Oligodendrocytes (increased number of larger ones)
What reacts when there is necrosis of tissues?
Microglia
Where are microglia generally found?
Next to blood vessels
Where are microglial cells often seen?
Around infarcts and activated cells which have ingested lipids
What is cytotoxic oedema?
Intracellular swelling in acute cerebral ischaemia due to hypoxia
-Causes failure of ATP dependant ion channels so influx of ions (and therefore water)
What is vasogenic oedema?
Extravasation and extracellular accumulation of fluid in cerebral parenchyma
What is vasogenic oedema due to?
Infarction causing damage to the endothelium
and disruption of BBB so fluid can leak out
-At this point endothelium aren’t damaged enough to let out red blood cells
What can follow cytoxic oedema?
Vasogenic oedema
What occurs due to shearing trauma and what exact moment?
Diffuse Traumatic Axonal Injury
-Occurs at moment of injury
What forms at the site of sheared axons?
Axonal bulbs
