CNS Trauma: Cellular Response

Question 1

Neuron function:

Answer 1

Transmit impulses

-Usually neuron is biggest cell in a section

Question 2

Astrocyte function:

Answer 2

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

Question 3

Oligodendrocytes function:

Answer 3

Produce myelin

-Fewer and longer processes than astrocytes

Question 4

Microglia function:

Answer 4

Phagocytose intruders

-Slightly fewer processes than astrocytes

Question 5

Ependymal cells

Answer 5

Line ventricles

Question 6

What is the purple substance in neurons on slides?

Answer 6

Nissel substance

Question 7

What is everything in the CNS other than a neuron called?

Answer 7

Glial cell

Question 8

What does a silver stain of an astrocyte look like?

Answer 8

Yellow background, brown star like cell. The astrocyte processes show up well here, but they aren’t seen in a regular H&E section

Question 9

What does an astrocyte look like on H&E?

Answer 9

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

Question 10

What does an oligodendrocyte look like on H&E?

Answer 10

-Smallish, black dot, condensed, can’t see through, dark chromatin

Question 11

What do ependymal cells look like on H&E stain?

Answer 11

They line the ventricles.

• Have cillia & microvilli.
• Help make CSF!

Question 12

What do microglial cells look like on H&E?

Answer 12

Not remarkable.

• Look gunky/junk
• Don’t look nice and round
• Scrunched up macrophages

Question 13

What are some reactions neurons have to injury?

Answer 13

• Acute injury (red neurons)
• Subacute/chronic injury (degeneration)
• Axonal reaction, axonal spheroids
• Inclusions (viral or degenerative):
• -Cowdry bodies (herpes)
• -Negri bodies (rabies)

Question 14

What do red neurons in an infarct look like?

KNOW

Answer 14

• 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

Question 15

What does an axonal reaction look like?

Answer 15

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

Question 16

What do axonal spheroids look like?

Answer 16

• 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

Question 17

What disease are Cowdry A inclusions associated with?

Answer 17

Herpes (many types)

Question 18

What disease are negri bodies associated with?

Answer 18

Rabies

Question 19

What is gliosis?

KNOW

Answer 19

Astrocytes are proliferating, increasing in number

Question 20

Gemistocytic astrocytes

Answer 20

Get bigger, increase in size

Question 21

Cytoplasmic swelling

Answer 21

Something damaging, pumps in membrane of cell

Question 22

What do cowry inclusions look like?

Answer 22

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

Question 23

What do Negri bodies look like?

Answer 23

They’re associated with rabies

-Little, dark purple bodies in cytoplasm of neuron

Question 24

What does gliosis in the brain look like vs. a normal brain?

Answer 24

• 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

Question 25

What is the closest thing to making a scar in the brain?

Answer 25

Gliosis

Question 26

What do gemistocytic astrocytes look like?

Answer 26

-The look like cells that are getting bigger and increasing in size
-Many astrocytes proliferating due to injury
-They are making a lot of protein
-Slide looks very dense, dark purple due to cells increasing in size
Gemistocytic = looks big & plump

Question 27

What do rosenthal fibers look like? What are they associated with?

Answer 27

Dark pink processes that stick out of astrocytes.

• Look like connective tissue slide with some very dark pink spots
• tumors, injuries, metabolic disease

Question 28

What are corpora amylacea and where doe you see them?

Answer 28

• White/blue circles/structures that clump together in slide
• Amylated, blue pearls that happen naturally in aging
• Don’t mean anything pathological
• Collection of ___glycans

Question 29

How do oligodendrocytes react to injury?

Answer 29

• Don’t react much.

- Can die in demyelinating disorders though

Question 30

How do Ependymal cells react to injury?

Answer 30

• Don’t react much.

- Might see inclusions in CMV infection

Question 31

How do microglia react to injury?

Answer 31

• Proliferate
• Develop long nuclei, form nodules around dead cells
• EX: TB

Question 32

What are microglial nodules?

Answer 32

They are made by microglial cells in areas of dead tissue