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Flashcards in Intro to neuropathology Deck (27)
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1
Q

What is the mneumonic helpful for organizing neuropatholgy differential diagnosis?

A
  • VITAMIN C
    • Vascular
    • Infectious
    • Traumatic
    • Age-related or degenerative
    • Metabolic/toxic
    • Inflammatory (demyelinating)
    • Neoplastic
    • Congential/Developmental
2
Q

What are the different glial cells talked about in class?

A
  • Astrocytes
    • Oligodendrocytes
    • Ependyma
    • microglia
3
Q

The diffuse pink architecture seen on HandE stain of the cerebral cortex is what?

A
  • The fibrillary “matrix” of the cerebral gray matter, the neuropil,is formed by the cellular extensions (processes) of the neurons and glial cells. These processes fit together tightly, leaving a minimal extracellular space.
    • It is not extensive ECM, it’s tons of tiny dendrites and glial processes
4
Q

The bigger the soma, the bigger the…?

A

Axon

5
Q

A luxol fast blue stain can visualize what?

A
  • Myelin

* Usually added to HandE stain

6
Q

How many ways are there that a neuron can respond to injury?

A

• There are 4 ways the soma reacts to injury
• Total necrosis
• Chomatolysis
○ Injury at axon, but leads to a feedback-driven death of the neuron or regrowth of axon
• Acquisition of viral particles within nucleus or cytoplasm
• Acquisition of abnormal material within cytoplasm
○ Neurodegenerative processes
○ Storage disorders

7
Q

On a histology slide, what does an acutely damaged ischemic/anoxic neuron look like?

A
  • Red dead
    • Shrunken nucleus, large white surrounding “halo”
    • Eosinophilic cytoplasm
8
Q

What is indicative of a neuron going through chromatolysis on histology stain?

A
  • There is a super swollen cell body

* Trying to either regrow the axon or die in the process

9
Q

What stain better visualizes alzheimer’s disease?

A
  • Silver stain

* Compared to HandE much better

10
Q

If you see a slide and say: “storage disorder!” , what have you seen?

A
  • On HandE, the sea of pink is disruped not by healthy neurons but lots of swollen cytoplasms
    • Lots of “bubbles” of neurons that are distended with protein and junk
11
Q

What is wallerian degeneration?

A
  • Necrosis of the axon distal to a transection

* You may see swollen axonal processes by silver stains at the site of transection/injury

12
Q

What is the basis of the neuritic plaque in Alzheimer’s?

A
  • Response of axons to disease

* Disconnect from synaps and to aggregate around beta amyloid material in the brain parenchyma

13
Q

What is the best way to visualize an astrocyte?

A

• Full cytoplasmic volume of the astrocyte is best visualized by GFAP immunostaining

14
Q

How can you visualize the astrocyte reaction to injury?

A
  • They expand their cytoplasmic volume and synthesis of intracytoplasmic intermediate glial filaments
    • You can see this on GFAP immunostaining as well
    • On GFAP, the brown is a pocket around the blue RNA material
15
Q

Why can’t astrocytes fill in large holes of tissue damage?

A
  • They don’t produce extracellular collagen

* They can’t make “scars” because they don’t have the machinery to make it

16
Q

Where do ependymal cells live?

A
  • They line the ventricular spaces

* They also have ciliation

17
Q

What does neuronophagia look like on the slide?

A

• Lots of little balls of nucleus surrounding a red dead neuron

18
Q

How do the notes describe the microglia?

A
  • Sentinels within the brain, monitoring the immunologic milieu and awaiting need for response to tissue injury
    • They respond to injury and are replenished by blood monocytes
    • They are CD68 positive
19
Q

What happens in CNS hemostasis?

A
  • If the blood vessel is compromised,
    • Platlet adhesion and aggregation
    • Fibrin depostion and hemostatic plug
    • Release of signalling molecules by leukocytes
20
Q

What is going on in the repair phse of CNS traumatic injury?

A
  • Everything here is GLIOSIS
    • Astrocytic proccesses encircle lesion
    • No ECM deposition
    • Limited angiogenesis
    • Astrocytes produce inhibitory molecules preventing axonal regeneration
21
Q

After the hemostatic plug is in place, what happens in CNS traumatic injury?

A
  • BBB is reestablished
    • Reduced inflammatory cell recrutiemtn
    • Debridement is mediated by macrophages, microglia and astrocytes
    • Axonal breakdown
22
Q

What is the difference between type I and type II muscle fibers?

A
  • Type 1 is red, or slow twitch
    • More endurance, more mitochondria and myoglobin
    • Fire more tonically
    • Slower rates of contraction and relaxation
    • Type II is white, or fast twitch
    • More fatiguable
23
Q

At pH of 4.3 what is light and what is dark?

A
  • Type 1 is dark and type 2 is light
    • The opposite is true for the basic pH of 9.4
    • These are immunostaining tricks to differentiate
24
Q

What is different about myopathy vs. denervation?

A
• Myopathy
		○ Proximal weakness and atrophy
		○ Elevated CK
		○ EMG changes (specific pattern)
	• Denervation
		○ Distal weakness and atrophy
		○ Normal CK
		○ Different (specific pattern)
25
Q

What is the MUAP?

A
  • Part of the information in an Electromyography
    • A small needle in the muscle sums up the electrical activity of the motor units that depolarize
    • This is the signal used to diagnose pathology in muscle
26
Q

There are different patterns for acute vs. chronic denervation, what are they?

A

• Acute
○ Randomly distributed small, angular fibers are seen
○ Usually type II selective
• Chronic
○ Type I and ii proportion equalizes
○ TARGET fibers can be seen
• Reinnervation
○ Intact intrmuscular nerves undergo collateral sprouting
○ New synapses are formed with atrophic fibers
○ Fibers are converted to a single group based on the innervating neuron
○ Can show up as a large or small MUP

27
Q

During wallerian degeneration, what are the bands of bugner?

A
  • Basal lamina lined endoneurial tubes that ensheath proliferating schwann cells
    • Remember peripheral nerves can undergo fixing/remodeling
    • Macrophages and proliferating schwann cells are responsible for degrading myelin
    • This process can take months
    • Don’t forget the central chromatolysis in the cell body

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