Histology: Central Nervous System Flashcards

1
Q

What are the cells of neuroectodermal origin?

A
  • Neurons
  • Glial Cells

Cells of neuroectodermal origin include neurons and glial cells (astrocytes, oligodendrocytes, ependymocytes).

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2
Q

What are the cells of mesenchymal origin?

A
  • Microglia/macrophages
  • Meninges
  • Choroid plexus

Cells of mesenchymal origin include microglia/macrophages, cells of the meninges, and cells of the choroid plexus.

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3
Q

What is found in the cerebral cortex gray matter?

A

Cell bodies, synapses and dendrites

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4
Q

What is found in the cerebral cortex white matter?

A

Myelinated axons

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5
Q

Gray matter covers the white matter in the ___________

A

Cerebral Cortex - this is opposite in the spinal cord.

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6
Q

What does Nissl stain stain?

A

Rough endoplasmic reticulum

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7
Q

What are the characteristics of motor neurons (size, axon length, etc)?

A

– Large cell body
– Have long axons
– Nucleus with single large nucleolus
– Prominent Nissl substance

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8
Q

What are the characteristics of interneurons (local circuit)?

A

– Small compact cell body
– Lack Nissl substance
– Short dendrites and small axons

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9
Q

What is the role of the principal neurons?

A

They have long axons and transmit information over long distances - an example are the motor neurons

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10
Q

What is central chromatolysis?

A

In response to destruction of axons - neuronal cell body balloons and nucleus is displaced to the periphery with the dispersion of the ribonucleoprotein

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11
Q

Neurophagia

A

Damage to the cell body directly may lead to it beyond surrounded by microglial cells - commonly seen in viral infections

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12
Q

Acute Neuronal Injury

A

Irreversible injury with cell body shrinkage and increased cytoplasmic eosinophilia and loss of nuclear chromatin

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13
Q

Where is the nucleus seen in a ballooned neuron?

A

Still remains central

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14
Q

Negri Body Association

A

Rabies

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15
Q

Lewy Body Association

A

Parkinson’s Disease

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16
Q

Hirano Body Association

A

Alzheimer’s Disease but also noted in normal individuals with aging

17
Q

Function of Astrocytes

A

Aid with structure and repair of damaged neurons

18
Q

What are the main types of astrocytes?

A
  • Fibrillary

- Protoplasmic

19
Q

Fibrillary Astrocytes

A

White matter – majority with

numerous and extensive processes

20
Q

Protoplasmic Astrocytes

A

Gray matter – fewer branches

21
Q

Gliosis

A

A non specific nervous system reaction to injury and involves hypertrophy of astrocytes

22
Q

Function of Oligodendrocytes

A

Maintenance of function of myelin sheaths

23
Q

Are there glia in the peripheral nervous system?

A

NO. Schwann cells will perform the functions of the oligodendrocytes.

24
Q

What happens with loss of oligodendrocytes?

A

Leads to demyelination

25
Q

Microglia

A

Not “true” glia - they are monocytes that are CD68+ and act as phagocytic and Ag-presenting cells

26
Q

Where are microglia found?

A

Found evenly in the gray and white matter

27
Q

Ependyma

A

Specialized glia that line the ventricles and have cilia - no basement membrane is present though

28
Q

What is the function of ependyma?

A

Mainly as barrier between the brain and CSF

29
Q

Choroid Plexus

A

Made of folds of CSF secreting ependymal cells that protrude into the ventricles

30
Q

Pia Mater

A

Thin layer over the brain and the spinal cord