CNS Trauma: Cellular Response Flashcards
Neuron function:
Transmit impulses
-Usually neuron is biggest cell in a section
Astrocyte function:
React to injury
- Makes supportive/scaffolding structure of the CNS
- Provide food for cells in CNS
- Only source of glycogen
- Great capacity to proliferate
- Look star shaped
Oligodendrocytes function:
Produce myelin
-Fewer and longer processes than astrocytes
Microglia function:
Phagocytose intruders
-Slightly fewer processes than astrocytes
Ependymal cells
Line ventricles
What is the purple substance in neurons on slides?
Nissel substance
What is everything in the CNS other than a neuron called?
Glial cell
What does a silver stain of an astrocyte look like?
Yellow background, brown star like cell. The astrocyte processes show up well here, but they aren’t seen in a regular H&E section
What does an astrocyte look like on H&E?
It’s not as distinguishable as on silver stain. They look a lot like oligodendrocytes and are difficult to tell the difference between the two.
-Astrocytes are a little bigger & have open chromatin pattern that you can see through
What does an oligodendrocyte look like on H&E?
-Smallish, black dot, condensed, can’t see through, dark chromatin
What do ependymal cells look like on H&E stain?
They line the ventricles.
- Have cillia & microvilli.
- Help make CSF!
What do microglial cells look like on H&E?
Not remarkable.
- Look gunky/junk
- Don’t look nice and round
- Scrunched up macrophages
What are some reactions neurons have to injury?
- Acute injury (red neurons)
- Subacute/chronic injury (degeneration)
- Axonal reaction, axonal spheroids
- Inclusions (viral or degenerative):
- -Cowdry bodies (herpes)
- -Negri bodies (rabies)
What do red neurons in an infarct look like?
KNOW
- Cytoplasm becomes more eosinophilic as cell dies
- Shrunken, cytoplasm of the cell is red
- Red neurons usually indicate infarction
- Caused by blockage of blood flow
- Show up within 1 day
- Will be seen when blood supply is cut off
- Useful for evaluating an autopsy
What does an axonal reaction look like?
Large, pink, enflamed bodies
- Not a reaction in the axon, but a reaction in the cell body after axon is cut
- Cell is making TONS of protein to try to regrow the axon
What do axonal spheroids look like?
- Small, pink cells, sometimes with a boarder or with space around them
- They are inclusions in axons (cell bodies of neurons not seen)
- Not specific for one type of injury - sometimes trauma, others
What disease are Cowdry A inclusions associated with?
Herpes (many types)
What disease are negri bodies associated with?
Rabies
What is gliosis?
KNOW
Astrocytes are proliferating, increasing in number
Gemistocytic astrocytes
Get bigger, increase in size
Cytoplasmic swelling
Something damaging, pumps in membrane of cell
What do cowry inclusions look like?
It happens in the nucleus of the neuron
- Also called “owls eye” inclusions - looks like gigantic pupil in eye
- Large, dark circles taking up most of the cell at the periphery
What do Negri bodies look like?
They’re associated with rabies
-Little, dark purple bodies in cytoplasm of neuron
What does gliosis in the brain look like vs. a normal brain?
- Astrocytes are proliferating, growing in number
- Infarct has healed
- You can see processes extending from larger, more robust astrocytes
- Large gaps/holes seen in tissue
