How white blood cells fight pathogens-infection and response

• 4 types of pathogens are bacteria, protists, viruses, and fungi
• The immune system destroys pathogens and any toxins produced
• The immune system protects against the re-entry of the same type of pathogen
• Phagocytosis:

  • The phagocyte identifies a pathogen and attaches itself to it
  • The cytoplasm wraps around the pathogen and engulfs it, along with microorganisms
  • Unwanted products go into the blood and are sent to the kidneys for filtration
• Antitoxins:

  • Bacteria produce harmful toxins
  • White blood cells detect toxins and produce antitoxins
  • Antitoxins neutralize the effect of toxins
• Non-specific defence systems prevent pathogens from entering the body
• Lymphocytes:

  • Pathogens contain antigens, unique molecules on their surface
  • White blood cells produce antibodies in response to antigens
  • Antibodies lock onto antigens for destruction by other white blood cells
  • Antibodies are specific to a particular pathogen and are quickly produced
• Pathogens can be spread in 4 different ways:

  • Airborne
  • Direct contact
  • Indirect contact
  • Contaminated food and drink
• Features of non-specific defence systems:

  • Nose hairs collect dust and pathogens
  • Mucus traps pathogens
  • Trachea and bronchi produce mucus with cilia that waft it towards the throat for swallowing
  • Stomach produces hydrochloric acid to kill pathogens
  • Tears clean the eyes, and earwax cleans the ears
  • Skin forms a protective layer and produces sebum, an oily substance that kills bacteria
• Communicable disease:

  • A disease that can be spread from one person to another
  • Examples include measles, mumps, rubella, and malaria
• Non-communicable disease:

  • A disease that cannot be spread from one person to another
  • Examples include cancer, asthma, diabetes, and heart attacks