B6 Preventing and treating disease Flashcards
What are memory cells?
Types of WBC that remember the specific antibody needed to destroy a particular pathogen.
can become immune to diseases , antibodies can be made quickly in response to pathogens by WBC (immune system destroys before they cause any symptoms )
What is a Vaccine?
Its a treatment made of a dead inactivated form of a disease causing microorganism.
- stimulates natural immune response to invading pathogens
How do vaccines work?
- small amounts of dead/inactive pathogens are put into the body (ie injection)
- antigens in the vaccine stimulate WBC to make antibodies, which destroy antigens without risk of catching disease
- then immune to future injections by pathogen, body can respond rapidly with correct antibody as if previously infected
How do doctors use vaccines?
- protect against bacterial diseases (tetanus) AND viral diseases (polio, measles)
MMR vaccine protects against measles, mumps and rubella - smallpox: completely wiped out by vaccines
What is herd immunity?
When a large proportion of the population is immune to a disease, so the spread of the pathogen in the population is reduced
- whooping cough, 1970 UK
What are painkillers?
Drugs that treat and ease symptoms of diseases, but do not treat the disease itself
How can painkillers help treat symptoms?
-Aspirin and Painkillers, relieve headache and sore throat
- no effect on viruses that make you feel ill, still have to wait for immune system to overcome the pathogen to become well again
What are Antibiotics?
drugs that cure bacterial diseases
How do antibiotics work?
initially available in 1940’s
- ie penicillin
- damage bacterial cells without harming body cells
- can be taken as pills, syrup, or taken directly into bloodstream
- some kill a wide range of bacteria, some only work against specific bacteria
What are issues antibiotics face?
- cannot kill viral pathogens, no effect on diseases caused by viruses
-antibiotic resistant strains of bacteria are evolving, meaning some antibiotics no longer have an effect when they did before, so may no longer be able to cure bacterial diseases
Why is it hard to create antibiotics that kill viruses?
- viruses reproduce inside body cells, its hard to kill them without killing body cells
What are examples of drugs taken from plants?
Digitalis from Foxgloves- strengthen the heartbeat
Aspirin from Willow tree bark- anti inflammatory and pain relieving
How was Penicillin discovered? (drugs from microorganisms)
Fleming left lids off of his culture plates, after holiday, found mould growing on them
- noticed a clear ring of jelly around some of the mould spots, realised something had killed the bacteria covering the gel
- unsuccessfully tried to extract it, gave up
- 10 years later, Chain and Florey tried to extract and succeeded, also in proving it could cure bacterial infections (prolonged the lifetime of a man dying from a blood infection)
What are the factors of a good medicine?
- Effective (prevent or cure a disease, lessen symptoms effects)
- Safe (not too toxic or severe side effects)
- Stable (use medicine for a long time, stored in normal conditions)
- Successfully taken and removed from the body (cleared from system after its done)
How do scientists develop and test new drugs?
Preclinical testing: lab with cells, tissues and live animals
- target new drugs and make lots of possible new drugs, test their toxicity and efficacy on cells, tissues and organs. (Many chemicals fail)
- chemicals that passed the initial test, tested on animals, giving info on side effects and possible doses, used to predict how drugs will behave in humans
Clinical trials: healthy volunteer and patients
- low doses in healthy people, check for side effects
- safe, then tries on small number of patients. If effective, then larger scale trials take place for optimum dose
- passes all legal tests, licenced so doctors can prescribe it
-
