医学病理学课件Inflammation.pptVIP

Inflammation What is Inflammation? Why do we use anti-inflammatory drugs sometimes? Those who kill the microbes may also injure the normal tissues. When the reactions are too strong, prolonged or inappropriate, damage may become dominant. Related with chronic disease and cancer. Stimuli for Inflammation Infection Trauma and various physical and chemical agents Tissue necrosis Foreign bodies Immune reactions Recognition of Microbes, Necrotic Cells, and Foreign Substances Phagocytes, dendritic cells and epithelial cells… express receptors that sense the presence of infectious pathogens and substances released from dead cells. Toll-like receptors (TLRs) Inflammasome uric acid and extracellular ATP cholesterol crystals and free fatty acids Inflammation is a stereotyped response Dilute toxins Destroy causative agents Remove debris Isolate the damaged area Initiate repairing 5 cardinal signs Types of inflammation Acute inflammation Short duration Neutrophils (PMNs) accumulation Fluid and plasma protein exudation Chronic inflammation Longer duration Accumulation of M? and lymphocytes Proliferation of fibroblasts and blood vessels Features of Acute and Chronic Inflammation Acute inflammation Vascular changes vasodilation (hyperemia) increased vascular permeability (leakage) increased adhesion of leukocytes Cellular events cellular recruitment elimination the offending agent (activation) What increases the permeability? Endothelial cell contraction leading to intercellular gaps in postcapillary venules Endothelial injury (necrosis or detachment) Immediate Delayed Increased transcytosis of proteins Leakage from new blood vessels Hyperemia and leakage result in… Protein-rich fluid moves out (exudates and exudation) Fluid accumulation in extravascular spaces produces edema /effusion Stasis and Leuko- cytes margination Transudates Crosses intact membrane Most clear (acellular) Caused by hydrostatic imbalance or osmotic gradients Exuda