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Inflammation & Repair. Chronic Inflammation. Chronic Inflammation. Cell Types in Chronic Inflammation. Macrophages Types of Macrophages (fixed) Kupffer cells - liver Pulmonary alveolar macrophages Histiocytes - connective tissue Microglia - brain Osteoclasts - bone Spleen/lymph nodes
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Cell Types in Chronic Inflammation • Macrophages • Types of Macrophages (fixed) • Kupffer cells - liver • Pulmonary alveolar macrophages • Histiocytes - connective tissue • Microglia - brain • Osteoclasts - bone • Spleen/lymph nodes • Langerhans cells - epidermis
Other Cell Types • Lymphocytes • Plasma cells • Eosinophils • IgE mediated, parasitic infections • Mast Cells
Granulomatous Inflammation • Granulomatous inflammation • focal accumulations of activated macrophages with an epithelial-like (epithelioid) appearance. • Granuloma • microscopic aggregation of epitheliod macrophages surrounded by a collar of lymphocytes and occasionally plasma cells.
Granulation Tissue • Proliferation of new blood vessels and fibroblasts • Fibroblasts myofibroblasts
Wound Healing • Primary union (healing by 1st intention) • healing of a clean surgical incision • very little tissue damage is present • Secondary union (healing by 2nd intention) • healing of a large tissue defect
Healing by First Intention Healing by Second Intention 24 Hours
Healing by First Intention Healing by Second Intention 3 to 7 Days
Healing by First Intention Healing by Second Intention Weeks
Aberrations of Wound Healing • Inadequate granulation tissue/healing • Excessive repair • Hypertrophic scar • Keloid • Contractures
Conditions Inhibiting/Delaying Wound Healing • Poor local vascular supply • Poor oxygenation, decreased bacterial resistance, low temperature, and an acid pH • Deficiencies of vitamin C, protein, zinc • Infection • Tissue necrosis • Foreign material delay healing and acts as a nidus for bacterial infection • Excessive movement
Extracellular Matrix- Collagen - • Tropocollagen is the basic unit • Intracellular • procollagen • Extracellular • procollagen cleavage & lysine oxidation cross-linking • tensile strength
Wound Healing • Replacement of Type III collagen by Type I in wound healing will have a maximal tensile strength of 70-80% of normal (takes about 3 months)
The End Chronic Inflammation & Repair