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
Microglia
Not "true" glia - they are monocytes that are CD68+ and act as phagocytic and Ag-presenting cells
26
Where are microglia found?
Found evenly in the gray and white matter
27
Ependyma
Specialized glia that line the ventricles and have cilia - no basement membrane is present though
28
What is the function of ependyma?
Mainly as barrier between the brain and CSF
29
Choroid Plexus
Made of folds of CSF secreting ependymal cells that protrude into the ventricles
30
Pia Mater
Thin layer over the brain and the spinal cord