Why do microbes make us ill?
Bacteria and viruses rapidly reproduce in our body and produce toxins that make us ill
Viruses damage the cells in which they reproduce
How do our bodies respond to infection?
Phagocytes - ingest pathogen, kill them using enzymes
Lymphocytes - produce antitoxins and antibodies which bind to antigens
How did Semmelweiss contribute to medicine?
Puerperal fever was higher at one of his wards than another
He suspected this was due to doctors not washing their hands before dealing with pregnant women
Ssemmlweis published his theory in 1850.
It was not accepted by doctors because:
- germs were not discovered
- it would be more work for doctors to wash hands, stubbornness,
Now, recognized as a pioneer of antiseptic policy and prevention.
Antibiotics & Resistance
Destroy cell wall and kill bacteria
Resistance - when a pathogen is no killed by a particular treatment caused by a genetic mutation and natural selection e.g. MRSA
- a new strain is created and antibiotics are not effective.
- resistant strain survive and reproduce, as the body is not immune to it.
How to stop antibiotic resistance?
- complete the full course of antibiotics
- avoid overuse of antibiotics and using them when it is not appropriate
- now, antibiotics aren’t used to treat mild infections, such as mild throat infections to reduce development of resistant strains
Vaccinations
- people can be immunized by injecting inactive forms of a pathogen.
- stimulates WBCs to produce antibodies to destroy the pathogen.
- when in contact with the pathogen again, the body produces the correct antibodies at a faster rate.
How microbe cultures are grown?
- petri dish must be sterilised to kill unwanted microorganisms.
- inoculating loops used to transfer microorganisms to the media.
- the loop must be sterilized by being passed through a flame.
- the lid of the petri dish must be secured with adhesive tape to prevent microbes from the air contaminating the culture.
- in schools - must be incubated at 25 °C to prevent the likelihood of pathogens growing that are harmful to humans.
- industrial - higher temp. faster growth.
