|
|
| (3 intermediate revisions by the same user not shown) |
| Line 1: |
Line 1: |
| − | ==Introduction==
| + | #REDIRECT[[:Category:Degenerations and Infiltrations]] |
| − | * Degenerations and infiltrations are the morphological manifestation of an altered metabolism within the cell.
| |
| − | ** A particular kind of change within a cell or tissue may suggest that a specific type of alteration has occurred.
| |
| − | * Degenerations and infiltrations are types of structural changes.
| |
| − | ** These are best considered at a cellular level.
| |
| − | ** These structural changes are deviations from the cell's normal structure and function.
| |
| − | *** Parameters are outside the normal physiological range for the cell.
| |
| − | * '''Degeneration'''
| |
| − | ** The tissue cell shows some change in itself.
| |
| − | * '''Infiltration'''
| |
| − | ** Something accumulates in the cell or tissue.
| |
| − | | |
| − | ==[[Cellular Swelling]]==
| |
| − | | |
| − | | |
| − | | |
| − | ==[[Hydropic Degeneration]]==
| |
| − | | |
| − | | |
| − | | |
| − | ==[[Cellular Fatty Change]]==
| |
| − | | |
| − | | |
| − | | |
| − | ==[[Mucoid Degeneration]]==
| |
| − | | |
| − | | |
| − | | |
| − | ==Hyaline Degeneration==
| |
| − | | |
| − | * The term "hyaline degeneration" is applied to several types of degeneration or infiltration.
| |
| − | ** "Hyaline" is a descriptive term meaning "glassy".
| |
| − | *** Used in pathology when structureless material appears in section, and stains red with eosin
| |
| − | **** Describes a variety of conditions in which structureless materials are present.
| |
| − | * Is applied to both extra- and intra-cellular degenerations/ infiltrations. ** '''Extracellular'''
| |
| − | *** Protein hyaline casts in the renal tubules.
| |
| − | **** From excessive protein passing through glomerulus.
| |
| − | **** When fresh urine is examined under the microscope, casts may be seen as elongated glassy tubes.
| |
| − | *** Hyaline membranes
| |
| − | **** Proteinaceous effusions into pulmonary alveoli
| |
| − | **** Prevent gaseous exchange. ** '''Intracellular'''
| |
| − | *** Hyaline degeneration of skeletal muscle.
| |
| − | **** In vitamin E/ selenium deficiency.
| |
| − | * There are two forms of hyaline degeneration that deserve their own mention.
| |
| − | ** Fibrinoid degeneration.
| |
| − | ** Amyloid infiltration.
| |
| − | | |
| − | ===Fibrinoid Degeneration===
| |
| − | | |
| − | * Fibrinoid degeneration features a material which is fibrin-like.
| |
| − | * Is essentially a focal death of cells in the walls of small blood vessels (usually arterioles).
| |
| − | ** Parts of the vessel wall become replaced by a granular material.
| |
| − | *** Pinkish-red (i.e. eosin-staining).
| |
| − | *** Has some of the appearance and staining properties of fibrin.
| |
| − | *** Consists partly of degenerated muscle and elastic fibres, and partly of an increased amount of protein ground substance around the degenerated fibres.
| |
| − | *** Looks like a red smudge in the vessel wall when viewed histologically.
| |
| − | * The presence of the fibrin-like material may suggest
| |
| − | ** A local hypersensitivity reaction
| |
| − | ** Hypertension
| |
| − | | |
| − | ===Amyloidosis===
| |
| − | | |
| − | * Also known as amyloid infiltration
| |
| − | * Deposition of a proteinaceous hyaline substance in extracellular sites.
| |
| − | ** Sites of deposition vary with species.
| |
| − | * The kidney is a common site of deposition.
| |
| − | ** Amyloid is deposited under the capillary endothelium and progressively increases in volume.
| |
| − | * There are various categories of amyloid.
| |
| − | ** Is essentially an abnormal protein produced in the body
| |
| − | ** In most cases, it is produced in response to sustained antigenic stimulation caused by a chronic suppurative process.
| |
| − | *** E.g. a foot abscess, mastitis.
| |
| − | * Amyloid is a relatively inert substance.
| |
| − | ** When it accumulates, it is not easily removed.
| |
| − | | |
| − | | |
| − | | |
| − | [[Category:Degenerations and Infiltrations]]
| |
| − | | |
| − | | |
| − | ==Glycogen Infiltration==
| |
| − | | |
| − | * Glycogen is normally present in substantial amounts in the [[Liver - Anatomy & Physiology|liver]] and muscle.
| |
| − | ** Is a readily utilisable source of energy.
| |
| − | * Moderate glycogen infiltration in the [[Liver - Anatomy & Physiology|liver]]:
| |
| − | ** Grossly - doesn't have much effect.
| |
| − | ** Histologically - shows up as foamy cytoplasmic vacuoles, similar to that of fat.
| |
| − | * Some conditions may result in an increase in glycogen deposits.
| |
| − | ** [[DM|'''Diabetes mellitus''']]
| |
| − | *** Gives an increase in hepatic glycogen stores.
| |
| − | *** May be overshadowed by the increased fat in the hepatocytes, and therefore difficult to see.
| |
| − | **** Renal tubular deposits are more easily observed.
| |
| − | ** '''Excessive glucocorticoids'''
| |
| − | *** Could be due to:
| |
| − | **** Hyperadrenocortism
| |
| − | **** Animals being maintained on glucocorticoid therapy over a long period of time.
| |
| − | ***** Has more dramatic effect.
| |
| − | *** Huge amounts of glycogen infiltration.
| |
| − | **** [[Liver - Anatomy & Physiology|Liver]] appears larger and paler.
| |
| − | **** Vacuoles may be so extensive that the rest of the cytoplasm appear as pink strands passing from the nucleus to the plasma membrane.
| |
| − | ***** A "feathery appearance" or "web-like effect".
| |
| − | ** '''Glycogen storage diseases'''
| |
| − | *** Due to an inherited deficiency of an enzyme required for the breakdown of glycogen to glucose.
| |
| − | **** Cells continuously accumulate glycogen.
| |
| − | *** Seen in all tissues of the body but exerts its major effect in the CNS.
| |
| − | * Selective staining must be employed to distinguish glycogen vacuoles from fatty vacuoles in the [[Liver - Anatomy & Physiology|liver]].
| |
| − | ** Alcohol fixation is preferred.
| |
| − | ** Best's Carmine is the commonly used stain.
| |
| − | *** Stains the intracellular glycogen red.
| |
| − | | |
| − | | |
| − | [[Category:Degenerations and Infiltrations]]
| |
| − | | |
| − | | |
| − | | |
| − | ==Cellular Inclusions==
| |
| − | | |
| − | ===[[Viruses|Viruses]]===
| |
| − | | |
| − | * Either in the nucleus or cytoplasm.
| |
| − | | |
| − | ===Storage Products===
| |
| − | | |
| − | * Due to '''hereditary storage diseases''' in which there is a missing or defective cellular enzyme. There are many types known in domestic animals.
| |
| − | ** Break down/ build up of intracellular substances is halted.
| |
| − | *** The intermediate substance accumulates in the lysosomes.
| |
| − | ** Affects all tissues
| |
| − | *** The central nervous system is particularly vulnerable.
| |
| − | * Due to '''age'''
| |
| − | ** Lysosomes will accumulate non-degradable products
| |
| − | *** E.g. lipofuscin - the 'ageing' or 'wear and tear pigment'.
| |
| − | **** Commonly seen in middle-aged cats in the hepatocytes nearest the centrilobular veins.
| |
| − | | |
| − | ===Intracellular Bacteria===
| |
| − | | |
| − | * For example, [[:Category:Mycobacterium species|''Mycobacterium tuberculosis'']] in macrophages.
| |
| − | | |
| − | ===Protein Accumulation===
| |
| − | | |
| − | * In the renal tubular epithelium.
| |
| − | * Occurs when there is leakage of protein out through a damaged glomerulus.
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | [[Category:Degenerations and Infiltrations]]
| |