Lecture 8: Nonspecific Host Defense Mechanisms; The first line of defense agains
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- Natural Immunity is nonspecific. What three things are part of the nonspecific host defense mechanisms?
-
Phagocytes
Chemicals
Physical barriers - Normal Flora prevents pathogens from colonizing by producing ____ toxic to other bacteria.
- bacteriocins
- Normal flora prevent pathogens from colonizing by providing competition for ____ and _____.
- nutrients and attachment sites
- normal flora prevent pathogens from colonizing by creating an unfriendly environment. (secreting ____, ____).
-
acids
fatty acids - Normal Flora is present on body without causing disease. It prevents pathogens from colonizing by what three things?
-
- producing bacteriocins toxic to other bacteria
- providing competition for nutrients and attachment sites
- creating an unfriendly environment (secreting acids, fatty acids) - Skin. ____ and _____ provide a physical barrier to microorganisms.
- epidermis and dermis
- Although the epidermis and dermis provide a physical barrier to microorganims, ____ and ____ are natural portals of entry for pathogens.
- hair follicles and glands
- Name a pathogen that pushes itself through natural portals of entry (hair follicles and glands).
- Treponema pallidum (a spirochete) causes syphilis, an STD
- Skin is tough, dry (no water, no life), ___, ____, ____, covered with normal flora.
-
salty
oily
low in nutrients - Microorganims can be ____ with epidermis
- shed
- Name a protein in the skin.
- Keratin
- Keratin (protein in skin) is a poor source of _____
- carbon
- Name three things that are naturally antimicrobial.
-
- fatty acids
- acids
- sweat - ________ makes antimicrobial fatty acids with lipase
- Propionibacterium acnes
- Propionibacterium acnes makes antimicrobial fatty acids with _____
- lipase
- _____ ferment to produce acidic environment
- Staphylococci
- Staphylocci ferment to produce ____ environment.
- acidic
- Disease is more likely to occur if skin barrier is _____.
-
broken
ex: surgery, puncture wounds, bites, injections, etc. - Respiratory System. Airflow turbulent-microbes get stuck on ______
- mucosal surfaces
- ______ beat towards the pharynx (up the mucosal escalator).
- cilia
- Microbes sent up to mouth/nose, expelled by coughing or sneezing, or combined with _____ and sent to _____.
-
saliva
stomach - ____ destroys mucosal cells, disrupts action of the mucosal escalator.
- Smoking
- Mucous is full of ____, an enzyme that can break down peptidoglycan (a good thing).
- lysozyme
- Mucous is full of lysozyme, an enzyme that can break down ____
- peptidoglycan
- Besides mucous, lysozyme can also be found in ______
- lacrimal fluid (tears). This acts to protect eyes.
- If bacteria doesn't get sneezed or coughed out, it goes to the gastrointestinal tract. Stomach acid has a pH of ____ and is a natural barrier to pathogens.
- pH 2
- Stomach acid kills most everything, except ____ and _____, ______, ______
-
Typhoid and tubercle bacilli
protozoal cysts
certain viruses, Helicobacter pylori (causes stomach ulcers, can make environment a lower pH) - Name a virus that stomach acid can't kill.
- Helicobacter pylori
- Bile enters GI tract at _____
- duodenum
- GI tract is inhibitory to most microorganisms. Also duodenal enzymes will digest all the ____ and _____ components of microorganisms (proteins, carbohydrates, fats).
-
structural
metabolic - Name a pathogen that can get into your gastrointestinal tract. hint: it forms cysts.
- Giardia- a protozoan that forms cysts. Beavers poop it out into cold water. You drink water w/ cyst. It goes into stomach, then intestines. Cyst will become vegetative form. TROPHOZOITE form suckers. get diarrhea. lasts for 40 days.
- GENITOURINARY TRACT. Flow of urine prevents microbes from reaching ____ or _____
-
kidneys
bladder - Women get more bladder infections than men because?
- women have shorter urethra.
- pH of vaginal tract is kept low by _____ producing lactic/acetic acid as a result of glycogen fermentation.
- Lactobacillus.
- pH of vaginal tract ketp low by Lactobacillus producing lactic/acetic acid as a result of _____
- glycogen fermentation
- In ______ or _____ women, vaginal flora similar to adjacent skin.
-
pre-pubescent
post-menopausal - During child-bearing years, estrogen levels rise causing vaginal epithelial cells to secrete ____.
- glycogen
- Interferons stimulates production of _____ that interfere with viral reproduction in neighboring cells
- antiviral proteins (AVPs)
- Phagocytes include _____, ____(neutrophils, eosinophils)
-
macrophages
PMN cells (polymorphonuclear) - PMN cells inclue ____ and ____
- neutrophils and eosinophils
- ____ and _____ work together to confine pathogens to site of entry and fix damaged tissue
-
phagocytosis
inflammation - opsonin
- protein found on bacterium that enhances phagocytosis
- _____ is a response to injury (chemical, physical, or living organism)
- inflammation
- What are three types of injury?
-
chemical
physical
living organism - What are four signs of inflammation?
-
rubor
calor
dolor
tumor - Rubor
- redness
- Calor
- heat
- Dolor
- pain
- tumor
- swelling
- injured cells release ____
- chemicals
- _____, _____ respond to chemical signals such as _____ and arrive at site to begin phagocytosis
-
neutrophils
macrophages
histamine - _____ forms around pus.
- fibrin walls
- Pus is composed of ____, _____, _____, _____
- plasma, tissue cells, dead bacteria, leukocytes
- ______ develop from fibrin enclosing pus
- abscesses
- abscesses develop from fibrin enclosing pus (becomes a _____ if big)
- carbuncle
- Describe the process of inflammation.
- sunburn or mechanical injury introduces bacteria --> vasodilation (capillary walls open [dilate], releasing plasma) --> phagocytosis by neutrophils and macrophages --> fibrin walls form around pus --> abscesses develop from fibrin enclosing pus --> form a walled off site of injury
- Name a chemical messenger that causes vasodilation
- histamine
- Fever is an abnormally _____.
-
high temperature
Baby- if go over 100oF, not good.
Child- if go over 102oF, not good.
if 104, 105, must cool the person down quickly - Phagocytes engulfing parasites produce ____ such as ______ or _____
-
cytokines (chemical messenger)
interleukin-1
endotoxins - Phagocytes engulfing parasites produce cytokines such as interleukin-1 or endotoxins. These _____ (fever-inducers) travel in the blood to hypothalamus. What does the hypothalamus do?
-
pyrogens
hypothalamus raises body temperature - Fever results in ____ of blood vessels and an increase in overall ______
-
constriction
cell metabolism - Fever results in ____, ____
-
cold skin
chills and fever - Fever results in ______ of growth of certain microorganisms.
- inhibition
- fever results in more _____ repair and phagocytosis
- tissue
- Fever results in reduced blood borne ____ needed by parasites
- iron
- Fever results in what 5 things?
-
- Constriction of blood vessels and an increase in overall cell metabolism
- cold skin, chills and fever
- inhibition of growth of certain microorganisms
- more tissue reapir and phagocytosis
- reduced blood borne iron needed by parasites - Natural Killer Cells are like _____
- roaming assassins
- Natural Killer Cells picks out 'hits' by checking for _____
-
class I MHC (major histocompatibility complex proteins)
- Natural Killer cell surface receptor forms complex with class I MHC found on most cells - If no MHC or in reduced quantitites (as in cancer cells or virus-infected cells), Natural killer cells ____.
- kill
- Complement System is a series of ____
- proteins
- Complement System is a series of proteins. Proteins which act in a cascade (___ activates the others) to ____, _____ and _____ microorganisms.
-
C3
bind, coat, and destroy
*complement system is like a dogpile - Complement System is activated to _____
- destroy bacteria
- Give one example as to how the complement system works.
-
- Phagocytes release IL-6 after eating bacteria
- IL-6 stimulates production of lectin protein- binds mannose on bacterial capsule
- mannose is present on microbial cell walls, but not mammalian cell walls
- lectin binding activates complement pathway
- complement proteins dogpile
- protein encased bacterium destroyed by lysis or phagocytosis - When ____ and ____ bind together, activates C3, cascade occurs, complement proteins dogpile.
- Mannose and lectin
- Mannose (sugar), is just on _____ cells, not body cells
- bacterial