9. Normal Microbiota Flashcards
which areas of skin harbour more organisms?
moist, protected areas of skin, eg. armpits, groin or between the toes
in which parts of the body is organism density the greatest?
oral cavities and colon
what are normal flora?
organisms found in a given location in a state of health
what is colonisation?
establishment at a site in the body
what is symbiosis?
2 or more organisms co-exist in close physical association
what is mutualism?
both organisms benefit from the symbiosis
what is neutralism?
neither organism derives benefit or harm from the symbiosis
what is commensalism?
one organism benefits, the other one neither benefits nor is harmed
what is parasitism?
one organism (parasite) benefits at the expense of the other (host)
what are non sterile sites?
sites with normal flora, are exposed to the environment either directly or indirectly, and have no mechanism in place to maintain sterility
what are sterile sites?
those with no normal flora
when do humans acquire flora?
at birth
what are the 3 types of sterile sites?
- sterility maintained by surface cleaning
- sterility maintained by barriers that allow unidirectional flow
- sterility maintained by physical separation from non sterile sites
where is sterility maintained by surface cleaning?
those places that are open to the environment
efficient cleaning by ciliated epithelium, removal of bacteria by coughing, sneezing or swallowing
where is sterility maintained by barriers that allow unidirectional flow?
adjacent to non sterile sites eg. cervix and upper genital tract, urethra before urinary tract