infection and response

• what are pathogens?

  microorganisms that cause infectious (communicable) diseases
• do pathogens affect plants or animals?

  both
• how can pathogens spread?

  direct contact, water or air, vectors (organisms that carry and pass the disease without being infected)
• how can we reduce the spread of disease?

  • simple hygiene measure
  • destroying vectors
  • isolating infected individuals, so they cannot pass on the pathogen
  • vaccination
• 4 types of pathogen?

  viruses, bacteria, fungi, protists
• what happens if a pathogen enters the body?

  the immune system tries to destroy it
• how do white blood cells defend against pathogens?

  phagocytosis, antibodies, antitoxins
• what is phagocytosis?

  the white blood cell surrounds the pathogen, engulfs it and then digests it
• how do antibodies defend against pathogen?

  they attach antigen molecules onto the pathogen
• whats a toxin?

  a poisonous chemical, produced by certain pathogens
• what do antitoxins do?

  neutralise poisons of the toxins
• what are antibiotics?

  medicines that kill bacteria inside the body (cant destroy viruses)
• whats an issue with antibiotics today?

  bacterial strains resistant to antibiotics
• what is MRSA?

  a strain of bacteria resistant to antibiotics; a superbug
• how can we reduce the rate of antibiotic resistant bacteria development?

  1. doctors should only prescribe antibiotics if they are really needed
  2. patients must complete their course of antibiotics so that all bacteria are killed and none survive to form resistant strains
• what are non-specific defences?

  the first line of defence against pathogens in general; skin, hair, mucus etc
• what is an antibody?

  a protein produced by the immune system to kill specific pathogens
• what is an antigen?

  A molecule that triggers an immune response.
• whats a vaccination?

  a liquid containing inactive or dead pathogens, used to make the body produce antibodies to provide protection against disease
• what is digitalis?

  a drug extracted from foxgloves, use to treat problems
• what is aspirin?

  a painkilling drug extracted from the bark of willow trees
• what is penicillin?

  an antibiotic extracted from the penicillium fungus
• what is a double-blind trial?

  A trial where neither the participants nor the researchers know who is receiving the treatment and who is receiving the placebo.