NORMAL MICROBIOTA OF HUMANS Flashcards
- refers to living together or close association of 2 living organisms (each of diff species)
- can occur in various ways depnsing on the effect it brings to the symbionts
symbiotic relationship / symbiosis
2 living organisms of different species livings close together
symbionts
what are the 4 symbiotic relationships between microorganisms?
neutralism, commensalism, mutualism, parasitism
different microorganisms occupy the same ecologic niche, but have absolutely n o effect on each other
neutralism
beneficial to one symbiont and of no consequence to the other (neither beneifical or harmful)
commensalism
beneficial to both symbionts and similarly produces positive effect towards each other
mutualism
mainly beneficial to one sybiont and harmful to the other, usually leaves through form of a disease
parasitism
all microbes on and within the human body do not produce disease under ___ conditions
normal
___ microbes and ___ different species are present in the body
100 trillion; 500 to 1000
origin of microbiota in newborns
- exposure to mother’s genital tract
- exposure to skin and respi tract of those who handle the newborn
- general exposure to the envi
injected to the baby when born due to the absence of E.coli
vitamin K
2 types of normal microbiota in human
resident and transient
relatively of fixed types and are regularly found in a given are of the body at a given age
resident microbiota / flora
4 conditions for favorable growth
moisture, pH, temperature, nutrients
take up temporary residence on and within humans through their constant exposure to favorable external environment
transient microboita / flora
body sites that harbor knwon normal microbiota
- skin and mucous membranes
- eyes and ears
- mouth and respi tract
- GI tract
- genitourinary tract
which areas of the body are considered sterile or microbe free?
all internal tissues and organs and fluids within and organ or tissue
microbiota of the skin
bacteria and fungi (mostly anaerobes)
most common microbe of the skin
staphylococcus
location of microbiota of the skin
skin near mucosal opening and moist folds in the body
microbiota in the eyes are scant due to the flow of tears containing ___
lysozyme
which parts of the ear are sterile?
middle and inner ear
most common microbiota of oral cavity
streptococcus viridians group
this are of the respi tract is wehre the initial colonization of meningitidis, diptheriae, and pertussis occur
upper respiratory tract
why is the lower respi tract normally sterile?
organisms are destoryed by alveolar macrophages
microbiota that survives stomach acidity due to urease; can cause duodenal cancer
helicobacter pylori
why do few microflora exist in the small intestine?
due to peristalsis
where can you find the largest number of microbes?
large intestine / colon
true or false: the 5 cm distal urethra and the external meatus consist of numerous microbes
false: only 1 cm
which part of the genitourinary tract is not sterile?
vagina
common microbiota on the vagina of female infant
lactobacillus spp.
pH of vagina during 1 month - puberty
pH 7 neutral
pH of vagina during puberty until menopause
pH 4-5 acidic
pH of vagina after menopause
pH > 5
what are the advantaged of normal microbiota?
- production of nutrients
- microbial antagonism
- biotherapeutic agents
disadvantage of normal microbiota
opportunistic infections
