multiple layers of tightly packed cells, few pathogens can penetrate these layers, and
epidermis
shedding of dead skin cells removes microorganisms
dermis collagen fibers help skin resist abrasions that could introduce microorganisms
high salt concentration changes pH (messes with a narrow range that microbes need
sweat
thus killing them)
antimicrobial peptides act against microorganisms
defensins antimicrobial peptides that inhibit microbial growth
lysozyme destroy cell wall of bacteria (lyses cell)
secreted by sebaceous (oil) glands, helps keep skin pliable and less likely to break or
sebum
tear, also helps lower skin pH to a level inhibitory to many bacteria
line all body cavities that open to the outside of the body (nose, esophagus, GI tract,
mucous membrane
etc.)
a thin outer covering of the mucous membranes, living cells, tightly packed to prevent
epithelium entry of many pathogens, continual shedding of cells carries away microorganisms,
contain dendritic cells
dendritic cells located below epithelium and help phagocytize pathogens
goblet and ciliated columnar cells help remove invaders
mucous membranes produce chemicals that defend against pathogens
defense because it contains cilia and has peristalsis to expel stuff (also sticky so it traps
mucus
stuff)
produces and drains tears, blinking spreads tears and washes surface of the eye, and
lacrimal apparatus
contains lysozyme
lysozyme enzyme in tears that destroys bacteria
they are able to tolerate the introduction of antigens without eliciting an inflammatory
Immune priveleged sites
immune response.
microbiome competes with potential pathogens (normal flora keeps it in check
microbial antagonism
because their survival lessens survival of others)
normally harmless residents of the body that make up the human flora (all the microbes
microbiome
in a particular environment)
consumption of nutrients, create an how do members of the microbiome make it hard for pathogens to compete?
unfavorable environment, prevent
attachment to host cells, stimulates second
line of defense, and provides vitamins to
host
present in skin, mucous membranes, neutrophils and act against a variety of microbes
antimicrobial peptides
(not specific) by working in conjunction with other things
peptides small proteins
saliva washes microbes from teeth, gums, tongue, and palate (contain lysozyme)
stomach acid digests and or inhibits microorganisms (low pH)
gastroferritin sequesters iron being absorbed, making it unavailable for microbial use
bile inhibitory to most microorganisms
peristalsis moves GI contents through GI tract, constantly eliminating potential pathogens
defecation and vomitting two ways that the body can eliminate microorganisms
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