Test 3 - finals Flashcards
prions
infections proteins which when folded incorrectly will aggregate and lyse the cell
- whtn the proteins are released, they will infect surrounding cellls
prions are mostly found in
neurons
examples of a priod disease
spongiform
encephalopathy
mad cow disease
cuzfeld-jacob disease
mutualism
both partners benefit
endosymbiosis
one organism living inside the other
commensalism
one partner benefits without harming the other
paratism
one organisms lives at the expense of the other
cell damage
direct damage (prions lysing cell)
toxins
production of toxins that interfere with normal host physiology
exotoxins
secreted from cell, heat labile, highly toxic, antigenic, non-pyrogenic specific action
neurotoxins
affect nerve function (botulin, tetanospasmin
enterotoxins
interfere with interstinal lining
cytotoxins
kill host cell (lysis), anthrax, diptheria
endotoxins
gram negative, LPS (lipd A), low toxicity, heaqt stable, pyrogenic, weak, antigens, non-specific action
invasive factors
allow parasite to penetrate deeper into tissues where it causes more damage
Coagulase
dissolves basal collagen layer of epithelial tissue; bacgeria penetrate tissue
Fibrinolysin (streptokinsase)
dissolves fibrin clots used as body defense to isolate and trap cells in blood vessels in order to remove them easily and prevent proliferation
- if bacterial cell forms clot around itself, then this normal set of proteins will hide pathogen from body’s defense mechaisms
flagella
aid in projecting pathogen out of unideal conditions for survival
hyaluronidase
depgrade hyaluronic acid (make epithelial cells stick together)
antiphagocytic factors
allows parasite to avoid normal host defesne
capsule
allows pathogen to be unrecognizable to a phagocytic cell
botulism
caused by release of botulin toxin by Clostridium botulinum
- prevents release of acetylcholine
- flaccid paralysis
tetanus
caused by release of tetanospasmin by Clostridium tetani
- blocks acetylcholenesterase causing no uptake of acetylcholine
- convulsive paralysis (lockjaw)
disease transmissions:
portals of entry and exit
aerosols
direct contact
vectors
fomites
aerosols
tiny droplets of liquid which has potential to carry cells or viruses with it
direct contact
exchange of blody fluids; kissing, sexual intercourse, transfusion
vectors
other organism that are intermediate between source of infection and target of infection
fomites
inanimate objects that act as a transport mechanism for pathogens
different lines of human defense mechanisms
1st line of defense
2nd line defense
3rd line of defense
1st line of defense
skin, mucus, chemicals
2nd line of defense
phagocytic cells, complement, inflammation, fever
3rd line of defense
specific immune responses: lymphocytes, antibodies
Physical barriers
- skin (epidermis; dermis)
- mucuous membranes
- mucociliary escalaor
- lacrimation
- normal microbiota
skin epidermis
outer layer composed of multiple layers of tightly packed cells
- few can peneetrate
- contain keratin and collagen
- contains epidermal dendritic cells (langerhans cells)
- which phagocytize pathogens
- bacteria like streptococcus epiditimis act as competition for resources agains invading bacteria
skin (dermis)
contains protein fibers called collagen which give the skin strength and elasticity to resist abrasions that could introduce microorganisms
mucous membranes (epithelial mucus)
exposed to outside world
- thin, outer covering of the mucous membrane
- unlike surface epidermal cells, epithelial cells are living
- thightly packed to prevent enter of pathogens
mucociliary escalator
ensures mucus is not going into lungs
lacrimation
production of tears to rid eyes of particulate matter
normal microbiota
act as compeition
Leukocytes
White blood cells
- granulocytes
- agranulocytes
granulocytes
- nuetorphils
- basophils
- eosinophils
neutrophils
- highly phagocytic, motile, and are active in the initial stages of an infection
- they have the ability to leave the blood, enter an infected tissue, and destroy microbes and foreign particles
basophils
release substances such as histamine that are important inflammation and allergic resonses
eosinophils
- somewhat phagocytic and alos have the ability to leave the blood
eosinophils major function
- to produce toxic proteins agains certain parasites, such as helminths
- too small to destroy but can discharge peroxide ions to destroy them
agranulocytes
- monocytes
- lymphocytes
monocytes
- not actively phagocytic until they leave circulating blood, enter body tissues , and mature into macrophages
- dispose of worn out blood cells
lymphocytes
- naturla killer cells, t cells, b cells
nautral killer cells are found in
blood and spleen, lymp;h nodes, and red bone marrow
NK have the ability to
kill a wide variety of infected body cells and certain tumor cells
NK kill
any cell that displays abnormal or unusual plasma membrane proteins
the binding of NK cells to the target cell causes
the releases of vesicles containing toxic substances from NK cells
T cells and B cells
- not actively phagocytic
- play a role in adaptive immunity
- occur in lymphoid tissues of the lymphatic system and also circulate in blood
interferons
protein molecules tha tare released by host cells to nonspecifically inhibit the spread of viral infections
interferon stages
virally infected cell -> transformed into viral factory -> cell starts to produce interferons -> interferons do nothing for this infected cell -> interferons release and target a different cell -> stimulation of this new cell stimulates the production of anti-viral protein call AVP -> AVP hangs around in the cell -> when AVP is stimulated, the cell interacts with its own viral infection, the AV{ binds onto the ciral RNA -> this interferon, thus, stops the proliferatin of viral repliaation
Complement
- set of serum proteins designated numerically accordig to the order of their discovery
the activation of compliments causes
cell lysis (forein cell or your own cell) depends on what causes activtion and where activation takes place
classical compliment pathway
involves the stimulatioin of a complliment as a result of the actioin of antibodies binding to a target antigen
alternative pathway
stimulation of a compliment as a result independent of the action of antibodies
the end result of both complement pathways is
ring of proteins (MAC) that inserts itself into membrane of a target cell and forms a hole in the membrane and causes the cell to lyse
Phagocytosis
- chemotaxis
- adherence
- iingestion
- digestioin
- elimination or presentation
chemotaxis
movement
- microbial wastes stimulate migration of phagocytes to where the bacteria is located
- complements draw in phagocytes,
- cytokines
adherence
- attqachment
- opsonins increase ability of phagocyte to attach/engulf ot target cell
ingestion
creates vacuole around target cell
digestion
superoxide, peroxide, lysozyme (only affects gram +) hyppochlorite
ellimination or presentation
phagocyte releases waste product to surrounding area or presents them to surface
inflammation
- cell destruction releases kinins which stimulate the release of prostaglandins, histamine, leukotrienes
inflamation results in
vasodilation
- diapedesis (movement of WBC from blood to surrounding tissues), increased fibrinogen (increased production of clots)
fever
fever caused
- by interleukin 1
- occurs to increase the effects of interferons (work better and produced at higher rate)
- decrease iron availability so its unavailable for use in bacteria
fever causes
enzyme denaturation and nerve damage for the host
immunoglobulins
- antibodies
- IgG
- IgM
- IgA
- IgD
- IgE
IgG
- monomer
- consists of 80% of total IG, transplacental, high affinity for antigen; secondary response
IgM
pentamer
5-10%
First Ig produced
IgA
dimer
10-13%
secretory
mucuos, breast milk
IgD
<1%
B-Cell receptor
IgE
trace amounts
involved in allergic responses
immunoglobulins neutralizes
neutrolizes toxins by bindingn to it and making it non-functional
immunoglobulins causes and stimultes
- causes agglutination and opsonization
- stimulate complment activation
agglutination
- pathogens become connected to each other so thyre non-functional and easier for body to eliminate
opsonization
- iinvolves the binding of an opsonin (antibody) to an epitope on an antigen
after opsonin binds to the membrane what happenes
- phagocytes are attaracted to the pathogen
antigen
any substance which can cause the body to produce an immune response
- proteins dor arge polysaccharides
immune response
- production of specific blood proteins which will only react with the specific antigen which stimulated its production
antigenic compounds
components of invaiding microbes, such as capsules, cell walls, flagella, fimbriae, bacterial toxins, the coats of viruses, or the surfaces of other types of microbes
anibodies recognize and interact with specific retions on antigens called
epitopes or antigenic determinants
haptens
molecules which are targets of antibodies, but are too small to stimulate a response by themselves
exogenous antigens
microbe derived
endogenous antigens
produced inside the host cell
