EXAM 4 P3 Flashcards
consequences of disrupting gut flora
poor nutritional absorption and pathogen invasion
improper immune function, causing autoimmune disorders (asthma)
microflora of the skin
first line of defense
its dry, acidic, and salty conditions are not good for microbial growth
associated with anaerobes that grow in hair follicles and sebaceous fluids
what can cause flora to change
the weather, age, and hygiene
what is the predominant class of skin flora
gram positive cocci
residents of the upper respiratory tract/oral cavities
transient organisms get trapped in the mucus membrane (breathing) and are expelled (snot, sneeze)
common micro flora are gram positive cocci
lower respiratory tract
relatively sterile area
airborne and inhaled organisms are trapped in the upper tract and removed by ciliated epithelium
cough reflex and alveolar macrophages
microflora of the gastrointestinal tract
majority of microbes are located here
change with age
in what direction does pH increase
from the esophagus to the colon
inverse relationship to O2
stomach is extremely acidic (pH 2)
helicobacter
rare organism that grows in the stomach
survives pH2 environment
is a spirochete, good at moving through viscous fluid
can burrow into the mucous membrane lining of the stomach and modifies the environment to increase pH
damage due to helicobacter
damages human tissue, causing ulcers
can lead to gastric cancer if left untreated
Bacteroides
most abundant in the colon
positive, good at degrading complex polysaccharides found in fiber and grains
if they get into the peritoneal space, it can cause abscess and infection
Escherichia
aka E. coli
commonly used to track contamination (fecal in water)
methanobrevibacter
rare archaea
thano makes it a methanogen, producing methane (an odorless gas)
C difficile
number 1 hospital infection in the U.S.
normal gut inhabitant for most people
antibiotics can disrupt normal flora and allow it to spread. it becomes more resistant and can disrupt the colon
colitis
caused by an abundance of C difficile
aka mega colon
serious infection that can be fatal
to cure it, add more antibiotics to decrease the C diff population. is now a race to see is the normal flora will grow back first or the diff
most often C diff since it produces spores
probiotics
can repopulate the gut and prevent C diff from taking over and allowing normal flora to recover
fecal transplant therapy
first treated with antibiotics
fecal matter is collected by a donor, but in a blender with saline, and delivered to the colon.
cures 95% of C. diff infections
the other person may have viruses or bacteria that don’t both them, but may bother you unknowingly
beneficial functions of GI microflora
vitamin synthesis (thiamine, K, B12) gas production (CO2, CH4, H2) odor production (H2S, NH#) organic acid production (acetic, butyric) glycosidase reactions steroid metabolism (bile acids)
what do bile acids do
break up fats and oils into a more soluble state
genitourinary flora
upper urethra and bladder are generally sterile. flushing action of urine keep the bladder clear
UTI or bladder infections
anterior urethra
closest to the exit of the body (anus). can be colonized with gram negative organisms like E. coli. most don’t move up very far, but ones that do cause UTIs and kidney infections.
women’s urethra
shorter than men’s
more susceptible to UTI
vagina
flora of the vagina is one region that changes with age and physiological state
pre puberty and after menopause has streptococci and enterobacteria
during fertile years, pH is lowered and you find lactobacilli
capsules
extracellular polysaccharides
some bacteria produce specific proteins that will bind to the surface of a human cell.
fimbriae
short, highly abundant filaments on the surface of the cell
fixed and produce a lot of sticky surface area
pili
retractable
bind to something and retract to pull the other surface closer
puncture wounds
can disrupt O2 flow and allow things to grow (infection)
