B3 Flashcards
What is a pathogen?
- a microorganism which causes disease
What is a communicable disease?
- a disease which can be spread
Name the 4 types of pathogen
- bacteria
- virus
- fungus
- protist
Why do bacteria make us feel ill?
- they reproduce rapidly and release toxins which damage cells and tissues
Where are viruses found in the body?
- inside cells
How do viruses make us feel ill?
- they replicate inside cells which burst open to release the viruses
- this cell damage makes us feel ill
Explain the type of pathogen salmonella is , how it spreads, it’s symptoms and treatment/prevention
- its a bacteria
- it spread by bacteria ingested in food OR on food prepared in unhygienic conditions
- symptoms are : fever, abdominal cramps, vomiting and diarrhoea
- ways to treat or prevent : hydrate the body and wait for the infection to pass
Explain the type of pathogen gonorrhoea is , how it spreads, it’s symptoms and treatment/prevention
- its a bacteria
- it spread by sexual contact
- symptoms are : thick yellow (or green) discharge from the vagina / penis AND pain on urinating
- ways to treat or prevent : antibiotic = penicillin (although some bacteria are resistant) & prevent by using a condom
Explain the type of pathogen measles is , how it spreads, it’s symptoms and treatment/prevention
- its a virus
- it spread by inhalation of droplets from sneezes and coughs
- symptoms are : fever and a red skin rash (can be fatal)
- ways to treat or prevent : no treatment available BUT
prevent with vaccination
Explain the type of pathogen HIV is , how it spreads, it’s symptoms and treatment/prevention
- its a virus
- it spread by sexual contact OR exchange of body fluids (such as blood when drug users share
needles) - symptoms are : virus attacks the body’s immune system ALSO body unable to deal with other infections or cancers
- ways to treat or prevent : antiretroviral drugs
Explain the type of pathogen tobacco mosaic virus (TMV) is , how it spreads, it’s symptoms and treatment/prevention
- its a virus
- it spread by soil and direct contact between leaves
- symptoms are : discolouration on the leaves WHICH affects growth of the plant due to lack of photosynthesis
- ways to treat or prevent : no chemicals available OR remove diseased leaves
Explain the type of pathogen tobacco mosaic virus (TMV) is , how it spreads, it’s symptoms and treatment/prevention
- its a virus
- it spread by soil and direct contact between leaves
- symptoms are : discolouration on the leaves WHICH affects growth of the plant due to lack of photosynthesis
- ways to treat or prevent : no chemicals available OR remove diseased leaves
Explain the type of pathogen rose black spot is , how it spreads, it’s symptoms and treatment/prevention
- its a fungus
- it spread by water OR wind
- symptoms are : spots on leaves OR leaves turn yellow and drop early WHICH affects growth of the plant - photosynthesis is reduced
- ways to treat or prevent : Fungicides and/or removing ALSO destroying the affected leaves
Explain the type of pathogen malaria is , how it spreads, it’s symptoms and treatment/prevention
- its a protist
- it spread by mosquitoes biting infected people AND transferring the pathogen to healthy people
- symptoms are : recurring episodes of fever WHICH can be fatal
- ways to treat or prevent : stop mosquitoes, from
breeding AND use mosquito nets to avoid being bitten
What are the different parts of the defence system?
- the skin
- nose hair
- mucus
- cilia
- stomach acid
What is the role of the following parts of the defence system?
skin:
- stops pathogens entering the body. released chemicals to kill pathogens
nose hair:
- traps particles containing pathogens before they enter the body
mucus:
- released in the trachea to trap pathogens
cilia:
- line the trachea and move mucus (with trapped pathogens) up to the back of the throat to be swallowed
stomach acid:
- has hydrochloric acid which kills pathogens
What are the 3 functions of white blood cells?
- phagocytosis
- producing antibodies
- producing antitoxins
Describe what happens during phagocytosis
- white blood cells (wbc) engulf and digest the pathogen
Describe what happens during making antibodies
- pathogens have unique antigens (chemical markers) on the outside
- wbc make antibodies which attach to the foreign antigens. The antibodies are specific to the antigen for that pathogen
- the antibodies let other wbc find the pathogen to engulf and digest it
- the person is now naturally immune to a disease. If that pathogen enters the body again, the wbc can quickly make the antibodies before the person gets ill
Describe what happens during producing antitoxins
- antitoxins are chemicals which stop the toxins from the bacteria affecting the body
Describe how vaccines help to protect against future infections
- vaccination given:
- injected with a small amount of dead or inactive pathogen - antibodies produced:
- wbc produce antibodies to attack antigens - attract more white blood cells:
- more white blood cells produce antibodies - memory cells:
- these cells stay in the blood in case we are infected in the future - infection with same pathogen later on:
- wc can quickly respond and produce antibodies to kill pathogens
What are the advantages of vaccinations?
- vaccinations have helped to control diseases which used to be common e.g: polio
- when a large disease outbreak happens, we call this an epidemic
- this is stopped from happening if many people have been vaccinated
- this is because the disease cannot easily spread
What are the disadvantages of vaccinations?
- sometimes they do not work. We say the person has not got immunity
- cannot be used on people with a weakened immune system
- sometimes you can have a bad reaction to the vaccine e.g: swelling or a fever
What is an antibiotic?
- a chemical which kills bacteria
What is a pain killer?
- a drug which reduces pain and treats the symptoms of a disease (but does not kill the pathogen)
Why is it pointless to give antibiotics to someone suffering from measles?
- measles is a virus and antibiotics only work on bacteria, not viruses
Some bacteria can no longer be treated by antibiotics. Explain why
- they have mutated and become resistant to antibiotics, so they are no longer killed
What is the source of most drugs?
- plants
Where is aspirin produced and what is it used for?
- its produced in willow trees
- its used for painkillers
Where is digitalis produced and what is it used for?
- its produced in foxglove plants
- its used for treating heart conditions
Where is penicillin produced and what is it used for?
- its produced in penicillium mould
- its used for antibiotic - to kill bacteria ONLY
New drugs are tested for toxicity, efficacy and dose. What do these words mean?
- toxicity = if it is harmful and has any side effects
- efficacy = if the drug works
- dose = the concentration of drug which works best and how often it needs to be taken
What is pre-clinical testing?
- testing first on human cells and tissues, followed by live animals
Who takes part in clinical trials?
- both healthy volunteers and patients
Why are healthy people used at the start of clinical trials?
- to make sure the drug has no harmful side effects which may be masked by other symptoms
What precautions are taken at the start of clinical trials?
- only healthy people are used
- the dose starts off very low
What does the ‘optimum dose’ mean?
- the amount which is most effective
- has fewest side effects
When the drug is tested on patients, some are given a placebo. What is this and why is it given?
- a placebo is a fake drug. It is given to check that any improvements are down to the drug
- and not caused by any psychological effects
What is a double blind trial?
- when neither the doctor nor the patients know who is getting the real drug and who is getting the placebo
