Defence Against Pathogens Flashcards
What may bacteria and viruses do
Reproduce rapidly inside the body and produce toxins which make us feel ill
What do viruses do
Damage the cells in which they reproduce
How do white blood cells help to defend against pathogens
Ingesting pathogens
Producing antibodies which destroy particular bacteria/viruses
Producing antitoxins, which counteract the toxins released by pathogens
What does the immune system of the body do
Produces specific antibodies to kill a particular pathogen
Leading to immunity from that pathogen
What happens in some cases
Dead or inactive pathogens stimulate antibody production
What happens if a large population is immune to a pathogen
The spread of the pathogen is much reduced
What did Semmelweiss do
Recognised importance of hand washing in the prevention of spreading some infectious diseases
Insisted doctors washed their hands before examine patients
REDUCED NUMBER OF DEATHS FROM INFECTIOUS DISEASES
What do some medicines such as painkillers do?
Help to relieve the symptoms of infectious disease but don’t kill pathogens
What are antibiotics
Medicines that help to cure bacterial disease by killing infectious bacteria inside the body
What can antibiotics not be used to do
Kill viral pathogens which live and reproduce inside cells
What should specific bacteria be treated by?
Specific antibiotics
What has the use of antibiotics greatly reduced
Deaths from infectious bacterial diseases
What has overuse and innapropiate use of antibiotics increased
The rate of development of antibiotic resistant strains of bacteria
What does mutations of pathogens do
Produces new strains
Antibiotics and vaccinations may no longer be effective against a new resistant strain of the pathogen
What will the new strain do
Spread rapidly because people are not immune to it and there’s no effective treatment
What do antibiotics do
Kill individual pathogens of the non resistant strain
What do individual resistant pathogens do
Survive and reproduce so the population of the resistant strain increases
What are antibiotics used to treat nowadays
Non serious infections so the rate of development resistant strains is slowed down
How can people be immunised against a disease
By introducing small quantities of dead or inactive forms of the pathogen into the body
What do vaccines do
Stimulate the white blood cells to produce anti bodies that destroy the pathogens
Making the person immune to future infections by the microorganism
What does the body do if the microorganism tries to infect again in the future
It can respond by rapidly making the correct antibody, in the same way as if the person had previously had the disease
How do you grow micro organisms (agar culture)
- Sterilise agar jelly and Petri dish to kill unwanted microorganisms
- Put inoculating loop into Bunsen burner to sterilise
- Lid of Petri dish should be secured with adhesive tape to prevent micro organisms from the air contaminating it
What temp should cultures be incubated at
25 degrees reducing the likelihood of growth of pathogens that might be harmful to humans
What is a pathogen
A micro organism which causes infectious disease
