How Bodies Defend Against Disease Flashcards
What are pathogens?
Microorganisms that cause infectious disease
Where may viruses and bacteria reproduce rapidly?
Inside the body
What may viruses and bacteria produce that make us feel ill?
Poisons (toxins)
What do viruses damage?
The cells in which they reproduce
The body has different ways of protecting itself against…
Pathogens
What type of blood cell help defend against pathogens?
White blood cell
What 3 ways do white blood cells defend against pathogens?
Ingesting them, producing antibodies, producing antitoxins
What do the antibodies produced by white blood cells do?
Destroy particular bacteria and viruses
What do the antitoxins produced by white blood cells do?
Counteract toxins released by pathogens
What does the immune system produce?
Specific antibodies to kill a particular pathogen
When the immune system can produce specific antibodies to kill a particular pathogen, what are you?
Immune from that pathogen
What’s in a vaccine?
Dead or inactive forms of a pathogen, in small quantities
What do vaccines stimulate?
Antibody production
If a large proportion of the population is immune to a pathogen, what happens to the spread of the pathogen?
It’s very much reduced
What did Semmelweis recognise the importance of?
Hand washing in the prevention of spreading some infectious diseases
How did Semmelweis greatly reduce the number of deaths from infectious disease in his hospital?
By insisting that doctors washed their hands before examining patients
What do some medicines, including painkillers, help to relieve?
The symptoms of an infectious disease, but they don’t kill the pathogens
How do antibiotics cure bacterial disease?
By killing infectious disease inside the body
Why can’t antibiotics be used to treat viruses?
As the live and reproduce inside cells
What has the use of antibiotics greatly reduced?
Deaths from infectious bacterial disease
It’s important that specific bacteria should be treated by…
Specific antibiotics
What has overuse and inappropriate use of antibiotics increased?
The rate of development of antibiotic resistant strains of bacteria
What’s an example of a strain of bacteria that have developed resistance to antibiotics?
MRSA
How have many strains of bacteria developed resistance to antibiotics?
Natural selection of pathogens with mutations
To prevent further resistance arising, what’s it important to do?
Avoid over-use of antibiotics
What produces new strains of pathogen?
Mutations
What are antibiotics and vaccinations no longer effective against?
A new resistant strain of a pathogen
Why do new strains of pathogen spread rapidly?
Because people aren’t immune to it, and there’s no effective treatment
What will antibiotics kill?
Individual pathogens of the non-resistant strain
Once antibiotics have killed all of the non-resistant strain, what will the individual resistant pathogens that survive do?
Reproduce, so the population of the resistant strain increases
Now, what are antibiotics not used to treat?
Non-serious infections- mild throat infections
What happens to the rate of development of resistant strains now that antibiotics aren’t used for non-serious infections?
It has slowed down
The development of antibiotic resistant strains of bacteria necessitates…
The development of new antibiotics
What do vaccines make people?
Immune to future infections by certain pathogens
If a pathogen enters the body of someone who has been immunized against it, what happens?
Their body responds rapidly by making the correct antibody
What does the MMR vaccine protect children against?
Measles, mumps and rubella
What are uncontaminated cultures of microorganisms required for?
Investigating the action of disinfectants and antibiotics
To grow uncontaminated cultures, what must petri dishes and culture be?
Sterilised before use to kill unwanted microorganisms
To grow uncontaminated cultures, what must inoculating loops used to transfer microorganisms to the media be?
Sterilised by passing them through a flame
To grow uncontaminated cultures, what must the lid of the petri dish be?
Secured with adhesive tape to prevent microorganisms from the air contaminating the culture
In schools and college labs, what maximum temperature should cultures be incubated at?
25 degrees c
Why should schools and colleges incubate cultures at low temperatures?
To reduce the likelihood of growth of pathogens that might be harmful to humans
Why do cultures grown in industrial conditions incubate at higher temperatures?
To produce more rapid growth
