B6 - Preventing and Treating Disease Flashcards
What triggers an immune response?
- Antigens = molecules on surface of a pathogen to stimulate an immune response
- Specific features = specific response
How do vaccinations work? (2)
- Small quantities of dead or inactive forms of a pathogen introduced in the body
- These carry antigens which trigger lymphocytes to produce antibodies
How does a vaccination protect someone from a disease?
- If same pathogen enters the body, white blood cells respond quickly to produce the correct antibodies, preventing infection
What does herd immunity mean?
- Majority of the population vaccinated against a disease
- Everyone is less likely to get it
What is an antibiotic?
- Medicines that help to cure bacterial disease by killing infective bacteria inside the body
What are the advantages of using antibiotics?
- Greatly reduced death from bacterial infections
What is a major concern around the use of anitibiotics?
- Emergence of strains of bacteria resistant to antibiotics
What do antibiotics do?
- Kill bacterial pathogens, not viral ones
Why is it diffcult to develop drugs that kill viruses?
- Drugs usually damage the body tissues too
Where does the heart drug digitails originate from?
- Foxgloves
Where does the painkiller aspirin originate from?
- Willow
Who discovered penicillin?
Alexander Fleming
Where does penicillin originate from?
- Penecillum mould
How are most new drugs synthesised?
By chemists in pharmaceutical industry
Why do new medical drugs have to be tested and trialled before use?
To check they are safe and effective
What 3 things are new drugs tested for?
- Toxicity
- Efficacy
- Dose
What does toxicity mean?
- Side effects making the person ill
What does efficacy mean?
- If the drug works to treat the illness
What does dose mean? (2)
- Concentration of drug used
- How often
What does preclinical testing involve?
- Drug tested in labs in cells, tissues and live animals
What do clinical trials use?
- Healthy volunteers/patients
What does clinical testing involve? (2)
- Very low doses of the drug at start
- If it is safe, further trials done to find optimum dose
What is a double-blind trial?
- Group is given a placebo and another the drug
- Neither the doctor or the patient know who has been given what
Why are the drugs tested using a placebo?
- To prove that the drug is effective and to avoid bias
