The inflammatory response is the non-specific way in which the body responds when a pathogen damages body tissue

  • When tissue damage occurs, mast cells (localised) and basophils (circulating) release a chemical called histamine
  • Histamine causes local vasodilation and increases capillary permeability to improve the recruitment of leukocytes to the region
  • Damaged cells also release chemotactic factors which attract leukocytes to the site of infection
  • While inflammation is necessary to allow immune cells access to damaged tissue, there are unavoidable side effects
  • Increased blood flow causes redness and heat, while increased permeability releases fluids and causes swelling and tenderness
  • Inflammation can be either short-term (acute) or long-term (chronic)

Inflammatory Response



A fever is an abnormally high temperature associated with infection and is triggered by the release of prostaglandins

  • Fever may help to combat infection by reducing the growth rate of microbes (via the inactivation of microbial enzymes)
  • It may also increase metabolic activity in body cells and activate heat shock proteins to strengthen the immune response

A fever occurs when activated leukocytes release pro-inflammatory chemicals called cytokines

  • Cytokines stimulate the anterior hypothalamus to produce prostaglandins, which lead to an increase in body temperature
  • Up to a certain point a fever may be beneficial, but beyond a tolerable limit it can cause damage to the body’s own enzymes

Mechanism of Fever