Acute inflammation

• Inflammation


  Tissue damage that initiates a set of vascular and cellular events to clean up cellular debris, infectious organisms, and initiate repair
• Causes of inflammation


  • Physical trauma
  • Chemical trauma
  • Infectious microorganisms
  • Sunlight and burns
• Gram-negative bacteria


  Has a lipopolysaccharide layer on its outer lining, with lipid A that can act as endotoxins
• Antigen


  Sugar molecules, protein molecules, or glycoproteins on the surface of bacteria that are immunogenic (able to activate immune cells) and reactive (able to induce antibody production)
• Incomplete antigen


  An antigen that is not fully immunogenic and reactive, such as the urushoil oil in poison ivy, which needs to bind to skin proteins to become a complete antigen
• Endotoxins from gram-negative bacteria can damage tissue cells
• Mast cells


  Cells with receptors that can be activated by endotoxins to initiate an inflammatory response
• Inflammatory response initiated by mast cells

  1. Endotoxins damage or activate mast cell receptors

  2. Mast cell sends signals to nucleus

  3. Preformed granules (Weibel-Palade bodies) released
• Chemotaxis


  White blood cells attracted to the area by chemical signals
• Adhesion


  White blood cells adhere to vessel walls, preparing to enter tissue
• Diapedesis


  White blood cells pass through vessel walls into the tissue
• Phagocytosis


  White blood cells engulf and digest foreign particles, bacteria, or dead cells
• Plasma Leakage


  Fluid and proteins leak out of blood vessels, causing swelling and edema
• Increased Permeability


  Capillary walls become more permeable for fluid and white blood cells
• Vasodilation


  Increased blood flow to the affected area
• ICAM-1


  Intercellular adhesion molecule-1, involved in acute inflammation response
• Migratory Response


  White blood cells move towards the source of the signal
• Opsonization


  Antibodies attaching to foreign particles for easier phagocytosis
• Phagocytic Cells


  Mainly neutrophils and macrophages engulfing and digesting foreign particles