Chap- 10 Disease & immunity

• Antibody molecule


  • Foreign pathogen surface antigen (enter our body)
  • New lymphocyte produce antibody
  • Antigen & antibody- complementary lock on
  • Antigen & antibody complex destroy antigen or pathogen
• Active immunity


  • Natural
  • Protein
  • Role of antibody
  • Formation of lymphocyte memory cells
  • Long term immunity
• Artificial (vaccine)


  • Dead antigen or weaker
  • Role of antibody memory cells
  • Long term immunity
• Active immunity


  • Antigen enter
  • Antibody by lymphocyte (own antibody)
  • Memory cell
  • Long term immunity
• Passive immunity


  • Ready made antibody
  • No memory cell
  • Short term
• Pathogens are organisms that cause disease (pathogens are passed, or transmitted, from one person to another). Eg- bacteria, viruses, fungi, protoctists and worms.
• Defences against disease


  • First line prevents pathogens entering the body
  • Second line destroys any pathogens that break through the first line and enters the blood
  • Third line produces antibodies that defend us against specific pathogens
• Mechanical barriers


  • Dead outer layers of the skin
  • Hairs in the nose trap larger particles
• Chemical barriers


  • Stomach makes hydrochloric acid that kill pathogens in food
  • Cells that line the airways make mucus that traps small dust particles and microorganisms
• White blood cells


  • Phagocytes engulf bacteria and viruses into vacuoles where they are digested and destroyed
  • Lymphocytes produce antibodies
• Vaccination

  Way to make lymphocytes produce antibodies and give long-term protection against certain diseases
• Active immunity


  • Defence against a pathogen by antibody production in the body
  • Can be acquired through natural immunity or vaccine-induced immunity
• Antigen


  Pathogen has antigens on their surface
• Antibody


  • Lymphocytes produce proteins called antibodies
  • Specific antibodies have complementary shapes that fit specific antigens
  • Antibody mark pathogen for destruction by phagocytes (phagocytosis)
• Ways antibody molecules attack pathogens


  • Cause bacteria to stick together in a group
  • Attach to the flagella of bacteria and stop them moving
  • Antitoxins combine with the toxins so neutralizing them and making them harmless
  • Kill bacteria directly by 'punching' hole through their cell walls
• Vaccination

  • Injection a vaccine that contains live pathogens, dead pathogens or antigens taken from the surface of pathogens
  • Vaccine contains harmless/ attenuated/ dead pathogen
  • Antigens are present on pathogens
  • Antigen stimulates an immune response
  • Lymphocytes produce antibodies which have complementary shapes that fit specific antigens
  • Antibodies destroy pathogen
  • Lymphocytes also produce memory cells
  • Rapid immune response if exposed to same pathogen
  • Provides long term immunity
• Passive immunity


  • Antibodies may be given by injection
  • Provides only temporary immunity
  • Antibodies pass across the placenta and are present in breast milk
  • Immunity is gained without exposure to antigens, so is much safer than active immunity
  • No memory cells are produced, so this type of immunity is short-term, but it is instantaneous
• Malfunctions of the immune system cause a variety of diseases that are collectively known as autoimmune diseases.
• Type 1 diabetes


  • Immune system attacks and destroys the cells of the pancreas that make insulin
  • Symptoms: Weight loss, Thirst, Tiredness, Increased urination and glucose in urine, Blurred vision, Poor wound healing, Confusion, unconscious and coma
• Treatment for Type 1 diabetes


  Regular injections of insulin, insulin pump, regular blood glucose tests, diet control