Immune System

• Immune system


  Extremely important in keeping you healthy
• Non-specific defense mechanisms


  • Skin
  • Hair
• Non-specific defense mechanisms are not enough to stop pathogens from entering the body


  Immune system gets activated to try and destroy the pathogens
• White blood cells


  Vital part of the immune system, help defend against pathogens
• White blood cell response to pathogens

  1. Identify pathogens

  2. Phagocytosis

  3. Antibody production
• Phagocytosis


  White blood cells called phagocytes engulf and digest pathogens
• Phagocytosis is a non-specific response, white blood cells can engulf any pathogen
• Antigens

  Unique marker proteins on the surface of pathogens
• Immune system recognises antigens as foreign


  Leads to a specific response, e.g. phagocytosis or antibody production
• White blood cells can recognise the body's own cells as foreign, leading to conditions like type 1 diabetes
• Antibody production


  1. B lymphocytes produce antibodies that bind to pathogens

  2. Antibodies help destroy pathogens through processes like phagocytosis
• There are many different types of antibodies, each binding to a specific antigen
• A single B lymphocyte only produces one type of antibody
• Antitoxins


  Produced by white blood cells to neutralise toxins produced by bacteria
• Antitoxins are different from antibodies as they don't bind to antigens on pathogens