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Cellular Elements of the NS & Non-Specific Rxns Injury
Lecture 1 Path course
51
Pathology
Professional
01/15/2011

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Cards

Term

What are the Cellular elements of the IMMature Nervous System?

Definition

  • Primitive, Pluripotential Neuroectodermal cells
  • Embryonal Tumors

 

Term
What are cellular elements of the Mature Nervous System? 
Definition

Neurons, Glia (Astrocytes, Oligodendroglia, Microglia)

Ependymal Cells 

Term
[image]
Definition

Centrum Semiovale

 

Large area of central, white matter subjacent to the cortex 

Term

 

What is the origin of the Neuron? 

Definition

 

Neuroectodermal 

Term
[image]
Definition

Pyramidal Neuron

Found in cerebral cortex, triangular, apex pointing toward surface, base downward,  myelinated axon arises from base to white matter

Term

 

Cortical Dysplasia

Definition
Seizure Disorder: total disarray of cortical neurons, loss of lamination and polarization --> jumbled, disorderly pattern. 
Term

 

Nissl Material

Definition

 

Characteristic of neurons. Consists of rosettes of polysomes and RER; has roles in protein synthesis. Found in nerve CELL BODY (perikaryon) and dendrites NOT axon hillock or axon. 

Term

 

How is the Nissl material distributed in Motor Neurons?

Definition

 

Coarse clumps and is called Nissl bodies

Term

 

How is the Nissl material distributed in Sensory Neurons? 

Definition

 

Evenly within the cytoplasm and is designated as Nissl substance

Term

 

Heavy Metal Stains

Definition

 

Ionic solutions of silver and gold used to illustrate elongated cytoplasmic processes. 

Term

 

Efferent limb of the Neuron

Definition

 

 

Single Axon: impulse destined to synapse with other neurons 

Term

 

Afferent Limb of neurons

Definition

 

Dendrites: receive impulses from the axons to other neurons

Term

 

Facilitation

Definition

 

Sum Total  of  + presynaptic impulses converging on 2 or 3 neurons from other primary neuronal sources, promoting discharge of an electrical impulse or firing. 

Term

 

Inhibition

Definition

 

Sum total of (-) presynaptic impulses converging on a 2 or 3 order neuron, PREVENTING discharge or firing 

Term

 

 

Summation

Definition

 

Sum Total of pre-synaptic + and - impulses converging on a 2 or 3 order neuron; if sum total is +, then will fire and vice versa. 

Term

 

Final Common Pathway 

Definition

 

Convergence of several facilitating and inhibiting presynaptic impulses from multiple neuronal sources upon 2 or 3 neuron, determining whether or not the neuron will fire

Term

 

Are neurons continuous or a syncytium?

Definition

 

Continuous

Term

 

Acute Neuronal Injury 

Definition

 

Variant of Coagulation Necrosis; shrinkage of the neuron (pyknosis), irreversible injury, NOT visible until 12+ hrs of post injury

Term

 

DEAD RED NEURON

Definition

  • entire cell shrinks (pyknosis)
  • cytoplasm become brick-red discoloration
  • nucleus shrinks and loses its cellular detail 
  • neuron does not regenerate (post-mitotic)

Term

 

Neurophagia

Definition

 

When macrophages engulf and ingest dead-red neuron. Also referred as Glial Nodule (esp. for viral and Rickettsial infections). 

Term

 

Ferruginization or 'mummification'

Definition

 

Injury to the CNS of a fetus or infant. Dead neurons are coated with mixture of calcium, protein & iron (mineralization). 

This process is also termed ferruginization or mummification; not removed by immature macrophages. 

Term

 

Parasagittal Region

Definition

 

In cerebral cortex, 1" lateral to sagittal fissure, border zone between anterior and middle cerebral artery

Term

 

Hippocampal Region

Definition

 

border zone of middle and posterior cerebral arteries. 

Term

 

Equator of the Cerebellar Convexity 

Definition

 

Equator of the cerebellar convexity between the superior and inferior cerebellar arteries. 

Term

 

Pathoclisis 

 

Definition
Selective Vulnerability: neurons inherent susceptibility to injury, based on intrinsic physiological, chemical and molecular differences.  
Term

 

Axonal Reaction

Definition

 

Swelling of neurons and poss. Reversible

Axon damage --> retrograde response of 1st neuron: nissl material disperse and invisible to microscope

Term

 

Central Chromatolysis 

Definition

 

Loss of nissl material in the central area of cytoplasm in Axonal rxn. 

(more info pending) 

Term

 

Trans-synaptic Degeneration 

Definition

 

Neuronal swelling and poss. REversible 

Injury occurs to the axon of pre-synaptic, 1st order neuron and post-synaptic neuron swells.

Term

 

Hypertrophy of the Olive

Definition

 

Ex. of trans-synaptic degeneration: many pre-synaptic neurons to inferior olivary nucleus are injured --> post-synaptic neurons swell --> diffuse enlargement of the entire structure. 

Term

 

Lipofuscin Granules 

Definition
Pigmented cytoplasmic inclusions that commonly accumulate with aging. They're considered residual bodies that are derived from lysosomes. 
Term

 

Neuromelanin

Definition

 

Normal intracytoplasmic neuronal pigment found in specific nuclei. Not related to melanin pigment of the skin and lost in pigmented nuclei in Parkinson's Disease. 

Term

 

Cowdry Type A intraNuclear Inclusions

 

Definition

 

Large, reddish-purple (magenta) intranuclear inclusions which displace the chromatin to the nuclear margin. 

 

Term

 

Ganglioglioma

Definition

 

"Ganglion Cell Tumor": neoplasm containing neurons 

Term

 

Astrocyte 

Definition

  • neuroectodermal origin
  • contain Glial Fibrillary Acid Protein (GFAP): which is a marker for astrocytes 
  • have cytoplasmic processes radiating from body, giving star app. and forming neuropil, in which neurons are embedded

Term

 

Protoplasmic Astrocytes 

Definition

  • located in Gray matter
  • plump cell body
  • thick cytoplasmic processes

Term

 

Fibrillary Astrocytes 

Definition

  • located in White matter
  • Spindled cell bodies
  • Thin, delicate cytoplasmic processes

Term

 

Gliosis 

Definition

  • non-specific rxn to injury
  • nucleus is eccentric and NO nucleolus
  • protoplasmic astrocyte reacts acutely
  • fibrillary astrocyte reacts in chronic mode

Term

 

Bergmann's Gliosis

Definition

 

Injury to the cerebellum results in activation of astrocytes within the plane of Purkinje cells 

Term

 

Alzheimer type II 

Definition

liver disease --> high ammonia levels --> nucleus swells 2-3x, loses chromatin and becomes watery clear

(also seen in Wilson's disease) 

Term

 

Rosenthal Fibers

Definition

A sign of non-specific rxn. to injury; intracellular and representing swollen astrocyte processes filled w/ glial filaments 

 

Term

 

Corpora Amylacea 

 

Definition

(Amyloid bodies)

  • round, gray-blue structures w/ concentric rings, which increase in proportion to age.
  • found in pial & subependymal & around blood vessels
  • Contain polyglycosan
  • found in LaFora's disease: systemic storage disease

Term

 

 

Oligodendroglia 

Definition

 

Myelin-forming cells of the CNS.

Term

 

How does an oligodendroglia cell show on H&E stain? 

Definition

  • nucleus looks like a lymphocyte: small, round and dark
  • nucleus w/ halo --> 'fried egg' appearance
  • 3-5 oligo... cells can surround cell body of neuron --> benign satelitosis 

Term

 

Multiple System Atrophy

Definition

 

  • Associated with Glial cytoplasmic inclusions (GCI) 
  • Sporadic olivopontocerebellar atrophy
  • Striatonigral degeneration
  • Shy-Drager Syndrome (Familial Dysautonomia) 

Term

 

Microglia 

Definition

  • Mesodermal Origin 
  • Arise from monocytes & fxn. as the scavenger cells (phagocytes) of the CNS. 

Term

 

How does the nervous system heal? 

Definition

 

By cavitation!!! 

Term

 

Rod Cells 

Definition

 

They form when spindled microglial nuclei become prominent in response to injury 

Term

 

 

Glial Nodules

Definition

 

focal constellation of neuronal ingestion

esp. for viral dzs

Term

 

Ependymal Cells 

Definition

  • line the central canal and ventricles, & luminal surface of choroid plexus, produce CSF
  • neuroectodermal origin
  • GFAP + cytoplasmic processes
  • blepharoplast: remnant of cilia, which disappears after birth

Term

 

Hydrocephalic Edema

Definition

 

Tight ependymal junctions are opened and CSF leaks into adjacent parenchyma 

normally ependymal have tight jxnions that are impermeable to the CSF --> barrier fxn. 

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