Block 8 (Neuro) - Histology Flashcards

1
Q

What are the two broad categories of CNS cells?

A
  1. Cells of neuroectodermal origin

2. Cells of mesenchymal origin

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2
Q

What are the cells of neuroectodermal origin?

A
  1. Neurons

2. Glial cells

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3
Q

What are the cells of mesenchymal origin?

A
  1. Microglia/macrophages
  2. Meninges
  3. Choroid plexus
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4
Q

What are the types of glial cells?

A
  1. Astrocytes
  2. Oligodendrocytes
  3. Ependymocytes
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5
Q

What are Nissl bodies?

A

Large granular bodies found in the RER of neurons

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6
Q

Where are grey and white matter located in the CNS and spinal cord?

A

CNS: gray matter surrounds white matter
PNS: white matter surrounds gray matter

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7
Q

What is the difference between white and grey matter?

A

White matter lacks cell bodies, dendrites, and synapses; it is made primarily of axons

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8
Q

What stain is used to see Nissl substances?

A

Cresyl violet

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9
Q

What stain is used to see axons and dendrites?

A

Silver stains such as the Bielschowsky stain

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10
Q

What is the Vimentin IH stain used for?

A

Astrocytes (intermediate filaments)

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11
Q

What is the Neurofilament (NF) IH stain used for?

A

Axons, dendrites, and neurons (intermediate filaments)

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12
Q

What is the Glial Fibrillary Acidic Protein (GFAP) IH stain used for?

A

Astrocytes and ependymal cells

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13
Q

What are the Synaptophysin and Chromogranin IH stains used for?

A

Neurons (cytoplasm)

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14
Q

What is the NeuN IH stain used for?

A

Neurons (nuclei)

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15
Q

What is the NSE IH stain used for?

A

Neurons

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16
Q

What is the S100 IH stain used for?

A

Astrocytes

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17
Q

What are the two main types of neurons in the CNS?

A
  1. Motor neurons

2. Interneurons (local circuit neurons)

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18
Q

Describe the appearance of a motor neuron on H&E stain.

A
  1. Large cell body
  2. Nucleus with single large nucleolus
  3. Prominent Nissl substance
  4. Long axon
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19
Q

Descirbe the appearance of an interneuron on H&E stain.

A
  1. Small compact cell body
  2. NO Nissl substance
  3. Short dendrites
  4. Small axons
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20
Q

What are 5 cellular responses of neurons?

A
  1. Chromatolysis
  2. Neuronophagia
  3. Acute neuronal injury
  4. Ballooning change
  5. Neuronal inclusions
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21
Q

What is central chromatolysis?

A

Characteristic change that occurs in the neuronal cell body due to destruction of axons. The rough ER disaggregates, the neuronal body balloons, the cytoplasm becomes smooth, and the nucleus moves to the periphery.

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22
Q

What is neuronophagia?

A

Prior to its death, microglial cells surround an injured/dying axon

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23
Q

What is a common cause of neuronophagia?

A

Viral illness

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24
Q

What is acute neuronal injury?

A

Irreversible damage to neurons; appears with cell body shrinkage, angularity, eosinophilic cytoplasm, condensation and pyknosis of the nucleus, and loss of nuclear chromatin

25
Q

What are some causes of acute neuronal injury?

A

Hypoxia, ischemia, hypoglycemia

26
Q

Pyramidal neurons in the ___ field of the ___ are vulnerable to acute neuronal injury.

A

CA1; hippocampus

27
Q

Pyramidal neurons in layers ___ and ___ of the neocortex are vulnerable to acute neuronal injury.

A

3; 5

28
Q

___ cells in the cerebellum are vulnerable to acute neuronal injury.

A

Purkinje

29
Q

What is a ballooned neuron?

A

Has enlarged cell bodies with homogenous cytoplasm and centrally placed nuclei

30
Q

What can cause ballooned neurons?

A

Corticobasal degeneration, Pick’s disease, prion disease, and physiological response to aging (in anterior horn cells)

31
Q

What are three types of neuronal inclusions?

A
  1. Negri body
  2. Lewy body
  3. Hirano body
32
Q

What causes a Negri body?

A

Rabies

33
Q

What causes a Lewy body?

A

Parkinson disease

34
Q

How does a Lewy body appear?

A

Large pink or purple bodies with a laminated structure found in the cytoplasm of pigmented neurons in the substantia nigra; these contain alpha-synucleon and shows a granular brown pigment

35
Q

What can cause Hirano bodies?

A

Alzheimers and Creutzfeld Jakob

36
Q

What are Hirano bodies?

A

Intracellular aggregates of alpha-actin

37
Q

What are the two types of macroglia?

A

Astrocytes and oligodendrocytes

38
Q

How do astrocytes appear on H&E?

A

Oval vesicular structure

39
Q

How do oligodendrocytes appear on H&E?

A

Smaller, more round, darkly staining nuclei

40
Q

How do astrocytes appear on a Golgi or GFAP stain?

A

Star-shaped

41
Q

What is the role of astrocytes?

A

Structural support and repair of neurons

42
Q

What are the two main types of astrocytes?

A
  1. Fibrillary (white matter) - majority with numerous and extensive processes
  2. Protoplasmic (grey matter) - fewer branches
43
Q

What are the two subtypes of astrocytes?

A
  1. Bergman glia (cerebellar cortex)

2. Pilocytic (periventricular, cerebellar, and SC white matter)

44
Q

What is gliosis?

A

The primary reaction of the CNS in which glial cells hypertrophy

45
Q

What are the two special types of gliosis and where are they seen?

A
  1. Bergman’s (around cerebellar infarcts)

2. Chaslin (subpial)

46
Q

What is the role of oligodendrocytes?

A

Formation and maintenance of myelin sheets

47
Q

Linear rows of this type of cell are common

A

Oligodendrocytes

48
Q

Why are oligodendrocites in grey matter referred to as satellite cells?

A

They cluster around cell bodies

49
Q

What are the 4 responses of oligodendrocytes?

A
  1. Loss
  2. Proliferation
  3. Inclusions
  4. Satellitosis
50
Q

Loss of oligodendrocytes leads to ___, as seen in what disease?

A

Demyelination; MS

51
Q

Where is proliferation seen?

A
  1. Edges of active MS plaques

2. Normal proliferation of oligodendrocytes during development

52
Q

When are inclusions seen in oligodendrocytes?

A
  1. JC virus in progressive multifocal leukoencephalopathy (PML)
53
Q

Microglia are derived from ___ and stain CD___+.

A

Monocytes; 68

54
Q

What are the functions of microglia?

A

Antigen-presenting cells and phagocytosis

55
Q

What are the cellular responses of microglia?

A
  1. Microglial nodules

2. Activated/transformed microglia

56
Q

What is the ependmya?

A

Specialized glia that line the ventricles; they form a single layer of cuboidal or columnar cells with cilia. There is no basement membrane.

57
Q

What is the choroid plexus?

A

Specialized organ made up of papillary folds of CSF secreting ependymal cells that protrude into ventricles; cobblestone appearance

58
Q

What are the three layers of meninges?

A
  1. Dura mater
  2. Arachnoid mater
  3. Pia mater