Lecture 4: Histology of CNS Flashcards

1
Q

What substance causes neurons to appear opaque in a histological staining?

What does it represent?

A

Nissl substance/bodies

Represents large, basophilic masses of free polysomes and Rough ER due to neurons being highly metabolic

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2
Q

What is the role of dendritic spines?

A

Known for their plasticity and ability to increase receptive area of the neurons

Increase in Surface Area

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3
Q

What are telodendria?

A

Dilation of branch ends of axons that contact postsynaptic cells

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4
Q

What is a neuropil?

A

The surrounding meshwork and structure that support the neuronal cell bodies

  • Works with glial cells*
  • Not part of cell body!*
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5
Q

What type of neuron is most common throughout the CNS?

What do they function as?

A

Multipolar

Motor neurons, CNS interneurons

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6
Q

What is the most common function of bipolar neurons?

A

Sensory neurons of retina, olfactory mucosa, and inner ear

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7
Q

What type of neuron is found in dorsal root and cranial ganglia?

A

Unipolar/Pseudounipolar

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8
Q

What motor protein is utilized in anterograde transport?

A

Kinesin (uses ATP)

Cell body –> axon

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9
Q

What motor protein is utilized by retrograde transport?

A

Dynein

Axon –> Cell Body

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10
Q

What is the speed of slow transport?

What type of transport is this utilized by?

A

0.2-4 mm/day

Anterograde

Examples: Cytoskeletal Elements

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11
Q

What is the speed of fast transport?

What is conveyed in either direction?

A

20-400 mm/day

Anterograde: Membrane-limited organelles, sER components, synaptic vesicles, mitos

Retrograde: membrane-limited organelles, molecules endocytosed at axon terminal (toxins and viruses)

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12
Q

Most synapses in the body are ___ synapses.

A

Chemical

Utilizing NT

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13
Q

How does electrical current pass through neurons?

A

Gap junctions

Connexon proteins connect pre and post synaptic membranes

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14
Q

On a histological image, what would differentiate between a chemical and electrical synapse?

A

Chemical synapse has a vesicular presynaptic cell

Electrical synapse has visible connexon protiens

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15
Q

What is the function of glial cells?

A

Support cells involved in conduction speed, repair, neurotransmitter maintenance

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16
Q

What are types of glial cells found in the CNS?

A
  • Astrocytes
  • Oligodendrocytes
  • Ependymal cells
  • Microglia
17
Q

What is the function of astrocytes?

A
  • Prevent leakage into Blood Brain Barrier
  • Moderate NT Intake
  • Clear Debris
18
Q

Astrocytes produce perivascular feet that perform what function?

A

Modulate blood flow and move nutrients and metabolites between neurons and capillaries

19
Q

What protein reinforces the proximal regions of astrocytes?

A

Glial Fibrillary Acid Protein (GFAP)

Stains Green

20
Q

What is the role of oligodendrocytes?

A

Myelinate axons from multiple neurons

Similar to Schwann Cells in PNS

21
Q

What type of epithelium are ependymal cells?

Where are they found?

A

Columnar or cuboidal cells lining ventricles of the brain and central canal of spinal cord

22
Q

What is the role of ependymal cells?

A

Facilitale CSF movement

23
Q

What is the choroid plexus composed of?

A

Thin layer of well-vascularized pia mater covered by cuboidal ependymal cells

24
Q

Where is choroid plexus found?

A

Roofs of 3rd and 4th ventricles

Parts of lateral ventricular walls

25
Q

What does the choroid plexus do?

A
  • Removes water from blood and releases it as CSF
  • Has tight junctions to prevent leakge of Blood-CSF barrier
26
Q

What are fronds?

A

Branches of choroid plexus that forms a villous structure

27
Q

What neural cells act similar to phagocytes and are the major mechanism of immune defense in the CNS?

A

Microglia

28
Q

In the spinal cord, where is gray and white matter located?

A

Gray Matter: Internal

White Matter: External

Sacral region has more gray matter than cervical

29
Q

How can you tell the difference between anterior and posterior horn?

A
  • Can look for motor cell bodies in anterior horn
  • Most of the time, anterior horn is bigger
30
Q

Where is the central canal located?

What is its significance?

A
  • Central commissure of grey matter
  • Lined by ependymal cells and has CSF
31
Q

What are the three layers of cerebellar cortex?

A
  • Molecular Layer: Lot of neuropil
  • Purkinje Cells: Thin layer with dendrites that extend through the moleculer layer
  • Granular Layer: Densly packed neurons
32
Q

What are the cerebral cortical layers?

A
  • Molecular Layer: Mostly neuroglial cells and horizontal cells of Cajal
  • External Granular Layer: Small pyramidal cells and granule cells
  • External Pyramidal Layer: Medium pyramidal cells
  • Inner Granular Layer: Small granule cells
  • Ganglionic Layer: Huge pyramidal cells (Betz)
  • Multiform Layer: Fusiform Cells
33
Q

What cortical layers contain the pyramidal cells?

A

Layer 2: Small pyramidal cells

Layer 3: Medium pyramidal cells

Layer 5: Large pyramidal cell layer - Betz Cells

34
Q

What tissue is this?

What is the outer layer? What is the deep layer?

A

Cerebral Cortex

  • Outer Layer: Molecular Layer
  • Deep Layer: Multiform Layer
35
Q

A patient’s MRI shows thinning of cerebral gyri in the frontal and temporal lobes. What disease process is associated with this finding?

A

Alzheimer’s disease

36
Q

What structures are found in a histological slide for a patient with this disease?

A

Amyloid B plaques

Neurofibrillary tangles: abnormal accumulation of tau

37
Q

Where is dopamine found?

A

Neuromelanin pigments in substantia nigra

38
Q

What are some features of Parkinson’s Disease on a histological slide?

A
  • Lewy Bodies
  • Pale halo
  • Aggregates of α-synuclein