Infection and Response Flashcards
What are pathogens?
Microorganisms that cause infectious disease
What are communicable (infectious) diseases?
Diseases that can easily spread
Name 4 types of pathogens
- Bacteria
- Viruses
- Fungi
- Protists
What is bacteria?
Bacteria are very small cells which can reproduce rapidly inside body
How can bacteria make you feel ill?
By producing toxins that damage your cells and tissues
Are viruses cells?
NO
How do viruses reproduce in your body?
- Live inside your cells and replicate themselves using cells’ machinery to produce many copies of themselves
- Cell will usually burst, releasing all new viruses
How do viruses make you feel ill?
Via cell damage (cell bursts, releasing all new viruses)
How does fungi cause disease?
Penetrate human skin and surface of plants, causing disease
How are parasites transferred?
Often by a vector which doesn’t get the disease itself
How do paraistes cause disease?
Live on or inside other organisms and can cause them damage
Name 3 ways pathogens can be spread
Though:
- Water
- Air
- Direct Contact
Explain how pathogens can be spread through water
e.g. Some pathogens can be picked up by drinking or bathing in dirty water
Explain how pathogens can be spread through air
e.g. Airborne pathogens are carried in air in droplets produced when you cough or sneeze & then can be breathed in (influenza virus is spread this way)
Explain how pathogens can be spread through direct contact
Some pathogens can be picked up by touching contaminated surfaces, including skin (on infected person)
Give 3 examples of viral diseases
MMR:
- Measles
- Mumps
- Rubella
How is measles spread?
By droplets from an infected person’s sneeze or cough
What are the symptoms of measles?
Red skin rash and fever
How is MMR prevented?
Most people are vaccinated against it when they’re young
Name 4 ways the spread of disease can be reduced or prevented
- Being Hygienic
- Destroying Vectors
- Isolating Infected Individuals
- Vaccination
Explain how destroying vectors prevents the spread of diseases
By getting rid of organisms that spread disease, you can prevent disease from being passed on
How can we get rid of vectors that are insects?
Can be killed using insecticides or by destroying their habitat so they can no longer breed
How can vaccinations prevent the spread of diseases?
Vaccinated people and animals = can’t develop infection and pass it on to someone else
Name 5 of your body’s defence systems
- The skin
- Hairs and mucus in your nose
- The trachea and bronchi secrete mucus
- The trachea and bronchi are lined with cilia
- Stomach produces hydrochloric acid
- Reproductive organs are slightly acidic and secrete mucus
Explain how the skin prevents the entry of pathogens (2 ways)
- Acts as a barrier to pathogens
2. Secretes antimicrobial substances which kill pathogens
What is purpose of hairs and mucus in your nose?
To trap particles that could contain pathogens
Why does your trachea and bronchi secrete mucus?
To trap pathogens
What are cilia?
Hair-like structures
What do cilia do?
Waft the mucus up to the back of the throat where it can be swallowed
Why does the stomach produce hydrochloric acid? (pathogen wise)
To kill pathogens that make it that far from the mouth
If pathogens make it into your body, your…
immune system kicks in to destroy them
How can white blood cells help to defend against pathogens?
- Ingesting pathogens
- Producing Antibodies
- Producing Antitoxins
What is called when white blood cells engulf and digest foreign cells?
Phagocytosis
What does every invading pathogen have on its surface?
Antigens
What do some types of white blood cell do when they come across a foreign antigen?
Produce proteins called antibodies
What do antibodies do and why?
Lock onto invading cells so they can be found and destroyed by other white blood cells
Why won’t antibodies lock on to all different types of pathogens?
Bc antibodies produced are specific to a certain type of antigen
What happens if a person is infected with the same pathogen again?
White blood cells will rapidly produce the antibodies to kill it = person is naturally immune to that pathogen and won’t get ill
When you’re infected with a new pathogen, why do you get pretty ill?
Bc it takes your white blood cells a few days to learn how to deal with it
What do vaccinations involve?
Injecting small amounts of dead or inactive pathogens
What does the dead/inactive pathogens (in vaccines) cause your body to do and why?
Cause your body to produce antibodies to attack them BC they carry (foreign) antigens
How does a vaccination make someone immune to future infections?
Bc if infected, white blood cells can rapidly mass-produce antibodies to kill off the pathogen = don’t get ill
Name 2 pros of vaccinations
- Helped control lots of communicable diseases that were once common in UK
- Big outbreaks of diseases (aka epidemics) can be prevented if a large percentage of population is vaccinated
Explain how herd vaccination prevent epidemics
People who aren’t vaccinated are unlikely to catch the disease because there are fewer people able to pass it on
Name 2 cons of vaccinations
- Vaccines don’t always work - sometimes they don’t give you immunity
- You can sometimes have a bad reaction to a vaccine (but it’s rare)
What are antibiotics?
Medicines that help to cure bacterial diseases by killing bacteria inside body
Different antibiotics kill…
different types of bacteria
What can mutations of bacteria produce?
New strains of bacteria that are resistant to antibiotics
What happens if you have an infection and some of the bacteria is resistant to antibiotics?
- When you treat infection = only non-resistant strains of bacteria will be killed
- Resistant bacteria will survive and reproduce (due to reduced competition) = population of resistant strain will increase
(example of natural selection)
What can a resistant strain cause?
A serious infection that can’t be treated by antibiotics
How can you slow down the rate of development of resistant strains?
- Doctors need to stop over-prescribing antibiotics
2. By finishing the whole course of antibiotics and not just stopping once you feel better
What is problem with new (resistant) strains?
They’ll spread quickly as people are not immune to it + they’ll be no effective treatment available
What do painkillers do?
Reduce the symptoms (affect the synapse)
What do antibiotics affect?
The cell wall of the bacterium
Why is it difficult to develop drugs that kill viruses?
It’s difficult to destroy virus without killing the body’s cell
