inflammation 5 Flashcards
chronic inflammation definition
inflammation of prolonged duration (Weeks to years) in which active inflammation, tissue destruction and attempts at repair proceed simultaneously
may follow acute inflammation or may skip acute inflammation
causes of chronic inflammation
persistent infections-by certain microorganisms
prolonged exposure to toxic agent
foreign bodies
autoimmunity-autoantigens evoke a self-perpetuating immune reaction
morphologic features of chronic inflammation
infiltration with mononuclear cells-macrophages, lymphocytes and plasma cells (b cells)
tissue destruction by persistent, offending agents or inflammatory cells
healing by connective tissue replacement=fibrosis (collagen)-angiogenesis+immature fibrous tissue=granulation tissue
acute vs chronic
acute-vascular changes, edema, and neutrophils
chronic inflammation-macrophages, lymphocytes, plasma cells, tissue destruction by inflammatory cells, and fibrosis
macrophage activation
microbial products-LPS (endotoxin)
cytokines-IFN-gamma
activation result in increased: cell size, lysosomal enzymes, metabolism and ability to phagocytose and kill ingested microbes
macrophages accumulate at site of chronic inflammation
continued recruitment of monocytes from circulation in response to chemotactic stimuli
local proliferation of macrophages
lymphocytes
involved in antibody and cell mediated immune reaction
lymphocytes migrate to sites of inflammation using adhesion molecules and chemokines
bidirectional interaction between lymphocytes and macrophages
plasma cells
developed from activated B cell
produce antibody at the site of persistent antigen
eosinophils
respond to parasitic infections or allergies (IgE)
granules contain major basic protein-toxic to parasites and causes tissue destruction
neutrophils
may be an important component in foci of chronic inflammation
granulomatous inflammation
distinctive pattern of chronic inflammation characterized by the presence of epithelioid macrophages +/- giant cells (fused epithelioid cells)
etiology-infectious agents and foreign substances
granuloma
focal area of granulomatous inflammation
central epithelioid macrophages surrounded by a collar of lymphocytes and plasma cells
caseous necrosis is seen with granuloma formation in some cases
systemic effects of inflammation
acute phase reactions
fever-due to synthesis of prostaglandins-tells the brain to increase temperature set point
synthesis of acute phase protein-C reactive protein, serum amyloid A, fibrinogen
leukocytosis-increased number of circulating leukocytes-accelerated release of leukocytes from bone marrow