Human Defense System

Innate Defenses

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Inflammation

  • Inflammation
  • Pathogens enter wound
  • Platelets release blood clotting proteins
  • Injured tissues and macrophages release cytokines to recruit help
  • Changes in capillary wall structure allow interstitial fluid and WBC's to leak out in tissue
  • Stimulate bone marrow to make and release additional nutrinophils and macrophages
  • Attract other immune system cells to the cite
  • Activate cells involved in tissue repair and wound healing
  • Induce fever
  • Mast cells release factors that constrict blood vessels at wound and dilate vessels nearby
  • Neutrophils arrive and begin phagocytizing pathogens
  • Leukocytes arrive and mature into macrophages
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Interferons

  • group of Proteins released by host cells in response to the presence of several pathogens, such as viruses, bacteria, parasites, and also tumor cells.
  • a virus-infected cell will release interferons causing nearby cells to stregnthen their anti-viral defenses.

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Natural killer cells

  • Type of lymphocyte
  • They control microbial infections and tumors from spreading far
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Complement