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| − | ==Hyaline Degeneration== | + | ==[[Hyaline Degeneration]]== |
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| − | * The term "hyaline degeneration" is applied to several types of degeneration or infiltration.
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| − | ** "Hyaline" is a descriptive term meaning "glassy".
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| − | *** Used in pathology when structureless material appears in section, and stains red with eosin
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| − | **** Describes a variety of conditions in which structureless materials are present.
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| − | * Is applied to both extra- and intra-cellular degenerations/ infiltrations. ** '''Extracellular'''
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| − | *** Protein hyaline casts in the renal tubules.
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| − | **** From excessive protein passing through glomerulus.
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| − | **** When fresh urine is examined under the microscope, casts may be seen as elongated glassy tubes.
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| − | *** Hyaline membranes
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| − | **** Proteinaceous effusions into pulmonary alveoli
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| − | **** Prevent gaseous exchange. ** '''Intracellular'''
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| − | *** Hyaline degeneration of skeletal muscle.
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| − | **** In vitamin E/ selenium deficiency.
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| − | * There are two forms of hyaline degeneration that deserve their own mention.
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| − | ** Fibrinoid degeneration.
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| − | ** Amyloid infiltration.
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| − | ===Fibrinoid Degeneration===
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| − | * Fibrinoid degeneration features a material which is fibrin-like.
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| − | * Is essentially a focal death of cells in the walls of small blood vessels (usually arterioles).
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| − | ** Parts of the vessel wall become replaced by a granular material.
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| − | *** Pinkish-red (i.e. eosin-staining).
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| − | *** Has some of the appearance and staining properties of fibrin.
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| − | *** Consists partly of degenerated muscle and elastic fibres, and partly of an increased amount of protein ground substance around the degenerated fibres.
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| − | *** Looks like a red smudge in the vessel wall when viewed histologically.
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| − | * The presence of the fibrin-like material may suggest
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| − | ** A local hypersensitivity reaction
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| − | ** Hypertension
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| − | ===Amyloidosis===
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| − | * Also known as amyloid infiltration
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| − | * Deposition of a proteinaceous hyaline substance in extracellular sites.
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| − | ** Sites of deposition vary with species.
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| − | * The kidney is a common site of deposition.
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| − | ** Amyloid is deposited under the capillary endothelium and progressively increases in volume.
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| − | * There are various categories of amyloid.
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| − | ** Is essentially an abnormal protein produced in the body
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| − | ** In most cases, it is produced in response to sustained antigenic stimulation caused by a chronic suppurative process.
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| − | *** E.g. a foot abscess, mastitis.
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| − | * Amyloid is a relatively inert substance.
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| − | ** When it accumulates, it is not easily removed.
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| − | [[Category:Degenerations and Infiltrations]]
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