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| | *** A local connective tissue response attempting to wall off the purulent irritant from nearby normal tissue. | | *** A local connective tissue response attempting to wall off the purulent irritant from nearby normal tissue. |
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| − | ===Functions of Exudate===
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| − | # Dilutes the toxic agent, reducing its effect upon the tissue cells.
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| − | # The protein components may contain antibodies which attack or coat (opsonise) the irritant.
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| − | #* This makes the irritant more digestible to neutrophils and macrophages.
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| − | # Exudates may contain fibrin.
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| − | #* This is very sticky - immobilises the irritant.
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| − | #* Provides a framework over which the leukocytes crawl to reach the irritant.
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| − | #* Fibrin is also chemotactic to neutrophils, bringing more of these cells into the injured area.
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| − | # Exudate on a suface will wash away the irritant.
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| − | #* E.g the skin and alimentary track.
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| − | # Brings the irritant to the lymph nodes, via the lymphatics, for further processing or antigen presentation.
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| − | #* Preferably within white blood cells such as macrophages and neutrophils.
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| − | #* Local lymph nodes may also be inflamed following inflammation of a tissue which drains into them.
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| − | ===Sequelae to Exudation===
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| − | * Catarrhal and serous exudationresolve when the irritant is overcome.
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| − | ** Alternatively, they may progress to a more serious reaction.
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| − | * Fibrinous exudates may also resolve if the fibrin is digested by macrophages.
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| − | ** In the pleural and peritoneal cavities, the fibrin may become rganised into fibrous tissue, producing adhesions between the visceral surface.
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| − | * Diphtheritic inflammation will only repair by scar formation.
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| − | * If haemorrhagic lesions are widespread, they most commonly associated with acute deaths.
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| − | ** For example in acute viral, bacterial or toxic diseases.
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| − | * If the exudation is strictly localised, for example in brusing, then repair may occur.
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| − | * The resolution of abscesses depends upon their location.
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| − | ** If the abscess is near to a surface it will rupture onto it.
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| − | ** This is beneficial in the skin where it discharges to the exterior, hopefully getting rid of the pyogenic organism.
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| − | ** If the abscess is in deeper tissues, there is extensive fibrous capsule formation.
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| − | *** The fluid becomes inspissated due to withdrawal of water content.
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| − | *** Macrophages digest the necrotic remains.
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| − | *** Fibrous tissue organises the interior.
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| − | *** The very end result is a fibrous scar.
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| | [[Category:Inflammation]] | | [[Category:Inflammation]] |
