preventing and treating disease

Cards (32)

  • give 4 ways in which the spread of pathogens can be reduced:
    • hygiene - handwashing, disinfectants, tissues
    • reducing contact with infected individuals - quarantine
    • removing vectors - use of pesticides and insecticides, removal of habitats
    • vaccination
  • why is it important to prevent the spread of viral diseases?
    scientists have not yet developed cures for many viral diseases
  • how can HIV/AIDS be prevented?
    • use of condoms
    • screening of blood for transfusions
    • not sharing needles
    • use of antiretroviral drugs to prevent the development of AIDS
  • how can the spread of salmonella be limited?
    • vaccinating animals intended for consumption
    • keep raw meat away from cooked meat
    • thoroughly cook meat
  • how can rose black spot be treated?
    • using fungicides
    • destroying infected leaves
  • how can the spread of malaria be reduced?
    • using insecticides
    • using insect nets to avoid bites
    • prevent mosquito breeding by removing stagnant water
    • antimalarial drugs
  • how can the skin prevent pathogens from entering the body?
    • the skin acts as a physical barrier
    • scab formation after skin is cut/wounded
    • antimicrobial secretions which can kill pathogens
  • how does the respiratory system prevent pathogens from entering the body?
    • nose - has hairs and mucus which trap pathogens
    • trachea and bronchi - have mucus that traps pathogens. ciliated cells move mucus to the mouth so it can be swallowed
  • how does the stomach prevent pathogens from entering the body?
    -secretes hydrochloric acid which kills any pathogens present
  • how does phagocytosis protect us against disease?
    white blood cells ingest and destroy pathogens so they cannot infect more cells
  • how does antibody production protect us against disease?
    • white blood cells produce antigens which are complementary to a specific antigen on a pathogen
    • the binding of antibodies to antigens causes pathogens to clump together, making them easier to destroy
    • in the case of a 2nd infection, the correct antibodies can be produced rapidly, preventing the person getting the same disease again
  • how does antitoxin production protect us against disease?
    antitoxins bind to toxins released by pathogens and neutralise them
  • vaccination
    contains a dead or inactive pathogen which stimulates white blood cells to produce complementary antibodies to the pathogen in the case of a second infection, memory cells can rapidly produce the correct antibodies and prevent illness
  • herd immunity

    a sufficiently high proportion of a population which are immune to a disease, the spread of a disease will be limited
  • advantages of vaccination
    • have eradicated many deadly diseases
    • epidemics can be prevented
    • herd immunity protects those who cannot have vaccinations
  • disadvantages of vaccinations
    • not guaranteed to work - might not protect against multiple strains of a pathogen
    • may be side effects or adverse reactions
  • how are bacterial diseases cured?
    with antibiotics that kill pathogens inside the body
  • how do antibiotics work?
    kill bacterial pathogens inside the body, but will not kill human cells
  • why do antibiotics not work to treat viral diseases?
    they have no effect on viral pathogens as they live inside the host's cells; therefore it is difficult to design drugs that would kill the virus and not destroy human cells at the same time
  • antibiotic resistance

    occurs when mutations lead to individua bacteria being resistant to an antibiotic. these bacteria are able to survive, reproduce and pass on their alleles, leading to a greater proportion of antibiotic-resistant bacteria
  • how can we prevent antibiotic resistance
    • avoid overuse and unnecessary use of antibiotics - e.g. only prescribe them for viral infections
    • finish the full course to ensure all bacteria is killed
  • painkillers -> infectious diseases
    only treat the symptoms but do not kill pathogens
  • what plant is digitalis extracted from?
    foxgloves
  • what painkiller originates from a willow bark tree?
    aspirin
  • what antibiotic was discovered by fleming?
    penicillin
  • what are the 4 qualities of a good medicine?
    • safe
    • effective
    • stable
    • able to be taken in and removed easily
  • what 3 factors are tested when developing new drugs?
    • toxicity
    • efficacy
    • dosage
  • preclinical testing

    -carried out in a lab
    -uses cells, tissues and live animals
  • clinical testing

    -uses healthy volunteers and patients
    1. drugs are tested at a low dose on healthy people
    2. then on patients and at a larger scale to find the optimum dose
    3. often, one group receives a placebo and another group receive the actual drug in order to assess the efficacy
  • single-blind trial

    only a doctor knows whether the patient is receiving the drug or the placebo
  • double-blind trial

    neither the patients nor doctors know who gets what
    -helps removes bias
  • peer review
    where the results of drug trials are checked over by the scientists knowledgeable in this field