Injured tissues and leukocytes secrete seratonin, histamine, kinins that constrict blood vessels and dilate arterioles causing redness and warmth in the tissues.
Blood flow increases (hyperemia) and edema forms at the site of injury or invasion. Increased blood flow also bring more nutrients to the injured tissue.
Capillary leak occurs - plasma leaks into tissues causing more swelling (protective as it forms a cushion. it also dilutes toxins and organisms in the area) and pain (protect the area from further injury by discouraging anymore stimulation).
Subsides in 24-48 hours.
Stage II: Cellular Response
Increased numbers of neutrophils or Neutrophillia occurs.
Arachidonic acid (AA) cascade starts to increase the inflammatory response.
Fatty acids in plasma membranes converts into AA.
Enzymes including coozygenase converts AA into other chemicals that gets processed into the substances (histamine, seratonin leukotriens, prostaglandins and kinins) that continue the inflammatory response in the tissues.
Antiinflammatory drugs work by preveningt cycloozygenase from converting AA into inflammatory substance.
Stage III: Repair and Replacement
WBC induce remaining healthy cells to divide.
In cells that cannot divide, WBC trigger new blood vessel growth (angiogenesis) and scar tissue formation.