Fighting diseases

• What does the skin do?

  Acts as a barrier to pathogens. It also secretes antimicrobial substances which kill pathogens .
• Hairs and mucus in your nose trap particles that could contain pathogens.
• The trachea and bronchi secrete mucus to to trap pathogens.
• What are the trachea and bronchi lined with?

  Cilia - hair like structures which waft the mucus up to the back of the throat where it can be swallowed.
• What does the stomach produce?

  Hydrochloric acid that kills the pathogens that make it far from the mouth.
• If pathogens do make it into the body, your immune system kicks in to destroy them.
• What is the most important part of the immune system ?

  White blood cells, travel around in your blood, constantly patrolling for microbes.
• What are three lines of attack of WBC?

  Consuming pathogens, Producing antibodies, producing antitoxins.
• What is phagocytosis?

  When white blood cells engulf foreign cells and digest them .
• Every invading pathogen has unique molecules called antigens.
• How do WBC produce antibodies?

  When some types of WBC come across a foreign antigen they will start to make proteins called antibodies to lock onto the invading cells so that they can be found and destroyed by other WBC’s.
• What happens after the antigens are destroyed?

  Antibodies are then provided rapidly and carried around the body to find all similar bacteria or virus.
• What happens if the person is infected with the same pathogen again?

  The WBC will rapidly produce the antibodies to kill it, the person is naturally immune to that pathogen and won’t get ill.
• What do antitoxins do?

  Counteract toxins produced by invading the bacteria.