a rapid and transient local reaction of the vascular and supporting elements of tissue injury. (high grade stimulus, high response)
examples of acute inflammation
NG, NP: no fibroblasts sent in
quick onset, short duration <6weeks, S&S: pain, heat, redness, swelling.
Aetiology of acute inflammation
Physical: mechanical -trauma, thermal-heat/hot, radiation- sunburn, radiotherapy. Chemical-etch,bleach,aspirin. Micro-organisms- viral, fungi, bacterial. Immunological-over expression (lupus, rheumatoid arthritis)
role of acute inflammation
remove necrosis, remove cause, protect, facilitate healing, allow access: WBC's, removal of toxins and bacteria.
How the body protects itself
Specific: Immune response. Non-specific: defence at body surface, phagocytosis, natural antimicrobial substances, inflammatory response, immunological surveillance
Cardinal signs of inflammation
(cellus in 1st century AD) CALOUR-heat (due to blood flow). RUBOR-red (increased blood supply). DOLOR-pain (nerve endings affected, pressure of blood supply). TUMOR-swelling (tissue fluid). (Gallen in 2nd century AD). FUNCIO LAESA-loss of function (due to all above allows time to heal)
Occurs in series of over lapping changes. stages are
1-Chemical factors released. 2-Vascular changes. 3-Cellular changes and cell movement. 4-Increased fluid exudate.
1- Chemical factors released
also known as chemical mediators or proinflammatory mediators. initiate and maintain response. increase number of leucocytes. (prostaglandins-produced by blood vessel walls, histamine-basophils)
2- Vascular changes
Transient vasoconstriction (1sec), Vasodilation of arterioles- slow flow to allow WBC to get out, Increased permeability- allows WBC out and plasma to leave
3- Cellular changes and cell movement
margination-neutrophil moves to margin. Rolling/adhesion. Transmigration. Chemotaxis- attracted by wound tissue damage itself. Demolition/phagocytosis
4- Increased fluid exudate
water, cells and cellular debris from blood vessels into tissue. Role: dilution of toxins, anti-bodies, medications, clotting agents (all to wound/infection). after infection/wound has healed exudate removes all above via lymphatic system.
Beneficial effects of acute inflammation
1-dilution of toxins and drainage to lymphatic system. 2- entry of defence cells. 3- transportation of drugs. 4- fibrin/clotting. 5- delivery of oxygen and nutrients to tissue. 6- stimulates immune response.
harmful effects of acute inflammation
1-digestion of healthy tissue. 2-swelling. 3-inappropriate inflammatory response.
factors that may delay healing in acute inflammation
infection, foreign bodies, reduced blood supply (smokers/diabetics), movement (no removal of bacteria and dead tissue)
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