Basic reactions to injury(张旭东–神经病理笔记系列之一) 自由微信 freewechat brain anoxia

Normal neurons, cerebral cortex: neurons come in many types and

Sizes, one of the most recognizable of which being the pyramidal neuron. Pictured here in cortical gray matter, the pyramidal neuron is notable for its triangular shape, prominent nucleolus (white arrow) andbasophilic nissl substance in the cytoplasm (black arrowhead).

Acute neuronal injury: neurons are vulnerable to cytotoxic stress.In acute neuronal injury, the cell shrinks, cytoplasm becomes deeply eosinophilic and nucleus appears pyknotic�the so called �red dead� neuron. In acute hypoxic encephalopathy, these changes are frequently observed in the cortex (layers III,V), hippocampus (CA1) and cerebellar purkinje layer.


Neurons, lipofuscin: in a variety of pathologic conditions, neuronsmay show inclusions.Brain anoxia in this case, lipofuscin appears as golden-brownmaterial accumulated in the cytoplasm. Lipofuscin is generally attributed to normal aging and is non-specific. Certain regions where neurons have abundant lipofuscin include the lateral geniculate nucleus (pictured), thalamus,inferior medullary olive, dentate nucleus.

Neurons, axonal injury: axonal swellings (or spheroids) appear when an axon is damaged (e.G. Trauma, infarction, degenerative or metabolic disease). They are composed of neurofilaments and organelles thataggregate as a result of interrupted axonal transport. They are usually numerous around the edge of an infarct.

Normal astrocytes, cerebral cortex: astrocytes (arrows) are support cells of the central nervous system.Brain anoxia pictured here in gray matter, thenuclei are smaller than pyramidal neurons (arrowhead) .

Astrocytic processes, GFAP stain: astrocytes� cytoplasmic processes are better visualized with special stains like this immunohistochemical stain for glial fibrillary acidic protein (GFAP) which allowsone to appreciate their stellate appearance .

Reactive astrocytes : in response to a wide variety of conditions,

Astrocytes undergo reactive changes (gliosis). Sometimes they swell with

Eosinophilic cytoplasm and enlarged nuclei with open vesicular chromatin. When this swelling is particularly prominent, they may be referred to as gemistocytes. Other times, they develop thickened processes creating apatternof fibrillary gliosis (also called piloid gliosis).Brain anoxia note the neuron in the bottom corner (arrowhead) with nissl substance in its cytoplasm distinguishing it from the reactive astrocytes.

Astrocytes, rosenthal fibers: rosenthal fibers are brightly eosinophilic

Corkscrew-like inclusions that may develop in astrocytes in chronic reactive or neoplastic conditions

Corpora amylacea: the corpora amylacea are spherical

Basophilic inclusions composed of polyglucosans, usually in astrocytic processes. They are common finding in normal brains, and tend to accumulate with age, mostly around the ventricles and subpial areas.

Normal oligodendrocyte: oligodendrocyte nuclei can be seen in white matter, often in short chains, and have smaller more dense nuclei than astrocytes.Brain anoxia practically speaking, normal oligodendrocytes may be difficult to distinguish from normal astrocytes, even for experienced pathologists. Oligodendroglia are the myelinating cells of the central nervous system�a function performed by schwann cells in the peripheral nervous system.

Microglia/macrophages: microglial cells are the macrophages of the central nervous system and often show a rod-shaped nucleus (a). When they become �activated�, microglia/macrophages phagocytose material and swell (b)–sometimes referred to as foam cells or gitter cells.

Normal meningothelial cells: the meninges consist of the pachymeninges (dura mater) and leptomeninges (arachnoid and pia; pictured).The arachnoid is covered by cap cells (arrows)�the origin of most meningiomas which invade/attach to the dura.Brain anoxia back

Normal ependyma: ependymal cells form a ciliated one-cell-thick layer throughout the ventricular system. Capable of regenerating earlier in life, later in life gaps are simply replaced by astrocytes. They have few reactive states including gaining inclusions in cytomegaloviral infection and forming nodules of glial processes (�granular ependymitis�) in chronic reactive conditions.

Normal choroid plexus: the choroid plexus consists of a fibrovascular tissue core covered by a single layer of cuboidal epithelium. With age, calcification is common (arrows).

下期预告:张旭东–神经病理笔记系列之二:

Cranio-spinal trauma

笔记作者:张旭东 兰大二院;编辑:李会琪

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