fighting disease

• How does the body prevent harmful pathogens from entering?

  1. skin acts as a barrier it has antimicrobial substances that kill pathogens
  2. hairs and mucus in the nose trap pathogens
  3. trachea and bronchi secrete mucus to trap pathogens
  4. trachea and bronchi lined with cilia to waft mucus back up to the throat to be swallowed
  5. stomach produces HCL
• what is the immune system made up of?

  lymphocytes and phagocytes
• what is phagocytosis?

  when a white blood cells engulf and digest foreign cells to destroy them
• how do lymphocytes fight pathogens?

  they detect the foreign antigen on the pathogen it will produce proteins (antibodies) to lock onto the pathogen so they can be found and destroyed

  • antibodies are specific to that type of antigen
• lymphocytes also produce...?

  antitoxins
• what are vaccinations?

  dead or inactive pathogens that carry antigens that causes your body to produce antibodies to attack them

  • therefore when a live pathogen that is similar in your immune system will be able to produce a rapid response
• what is the MMR vaccine for?

  measles, mumps and rubella
• what are the pros to vaccinations?

  • help control communicable diseases
  • smallpox no longer occurs and polio infections have fallen by 99%
  • epidemics can be prevented if a large percentage of the population is vaccinated
• what are the cons to vaccinations?

  • they don't always work and don't give immunity+
  • can cause bad reactions or severe ones like seizures
• How do drugs help to fight disease?

  painkillers: relive pain and symptoms

  antibiotics: kill the bacteria causing the problem without killing our body cells
• How does bacteria become resistant?

  Mutations can cause bacteria to become resistant to antibiotics

  • these strains will reproduce and increase their population
  • this may cause serious infection (like MRSA resistant to meticillin)
• How do you prevent bacteria from becoming antibiotic resistant?

  • not over-subscribing antibiotics
  • completing full course
• what is aspirin used for and where is it developed?

  used to lower a fever

  • developed in willow trees
• what is digitalis used for and where is it developed?

  used to treat heart conditions

  • developed from foxgloves
• what drug was extracted from microorganisms and how?


  penicillin

  • Alexander Fleming noticed that his petri dishes had mould but around it was a free from bacteria area
  • mould produced a substance that killed bacteria
• what are the three main stages of drug testing?

  1. preclinical testing on human cells and tissue
  2. preclinical testing on live animals
  3. tested on human volunteers in a clinical trial
• describe why the preclinical test on human cells and tissue is not completely effective?

  because some drugs need to interact with the body systems
• Describe the preclinical test on live animals?

  1. this is to test the drugs : efficacy (if it works), toxicity and the best dosage that should be given
  2. in Britain they must be tested on two different mammals
• Describe the clinical trial?

  1. tested on healthy volunteers to see if it has any harmful side effects (starts at a very low dosage and gradually increases)
  2. It is then tested on people with the illness and the optimum dose is discovered (most effective and few side effects)
  3. patients are put into two groups one with new drug and one with a placebo
  4. they are double blind so that doctors analysing patients are not subconsciously influenced
  5. drugs are then peer-reviewed to prevent false claims
• What does the organism penicillin originate from?

  penicillium notatum