Micro Exam 3*final* Flashcards
What are Kochs postulates?
A system for proving an organism is the cause of a disease
When are kochs postulates used?
For new diseases only because it takes too long to use for identification
What are the two cases when kochs postulates should be used?
Proving for the first time that a path. is the cause of a new disease
Settling disputes when two paths are reposted as the cause of the same disease
How many steps are in kochs postulates?
What are they?
AIIP
4 Association Isolation Inoculation Re-isolation
What is the association step in Knochs Postulates
The suspect must be present in all cases
A pathogen is suspected and is tested
What occurs during the isolation step of Knochs Postulates?
The suspect pathogen is isolated on agar medium using the 3 way streak method
What occurs during the inoculation stemp of Knoch Posts.
the suspect pathogen is innoculated into living host.
if the host shows the same symptoms as the original organisms then the next step is followed
What is the re-isolation step in Knochs P’s
the suspect ust be re-isolated from the inoculated host and must be identical
What are the exceptions of knoch’s rules?
Obligate parasites can not be isolated
Human diseases cant be tested on humans so results may not be accurate
What are non-specific host defenses?
defenses that target all types of pathogens
bodies first line of defense
What are the 7 types of non-specific defenses in humans?
ANAPIFM
Anatomical/physical barriers
Normal flora
Antimicrobial body secretions
What are the three main Anatomical barriers?
How do they protect?
Skin-water proof layer
Mucous Mem.-traps microbes
Cilia-mechanically removes foreign materials
How do normal human flora act as non-specific host defense?
immune system stimulation
Pre-coloization and takes up space
nutrient competition
production of toxins
lactobacillus
E. coli
What are the 5 main anti microbial secretions of the human body?
LPLTA
Lysozyme-saliva Peroxidase-saliva, milk Lactoferrin-milk Thiocyanates-saliva Acid- skin, stomach, vagina
What are the three main types of leukocytes involved in phagocytosis?
Macrophages
Monocytes
Neutrophils
What is the relationship between Macrophages and Monocytes?
When Macro’s die Mon’s can differentiate into Macros and replace them
Which of the three Leukocytes are the rapid response team?
Neutrophils
What are the 6 steps in Phagocytosis?
CRFFDE
Chemotaxis Recognition Formation of Phagosome Formation of Phagolysosome Destruction and Digestion Exocytosis
What occurs during Chemotaxis?
Phagocytes move to the site of infection via detection of chemicals produced by microbes
What occurs during Recognition
Receptors on Phagocytes bind to invading microbes
What is a phagosome?
When the cell wall of the phagocyte engulfs the microbe and creates a membrane-bound vacuole
Why is the production of the phagolysosome important?
it is what allows for the digestion and destruction of the pathogen within the phagocyte
What is inflammation?
the body’s response to tissue damage
What are the symptoms of inflammation?
increase in temperature of tissues.
redness
swelling
pain
How many main steps are in the inflammation process?
3
What occurs in the first stage of inflammation?
damaged cells release histamine
fluid rushes in
What occurs in the second stage of inflammation?
clotting begins
phagocytes enter tissue
head and redness begins
What occurs in the third stage of inflammation?
dead cells are removed, scab forms,
scar tissue forms
What is a fever and how does it at as a non specific host defence?
It is a systematic increase in body temp
caused by pyrogens
you body uses this defence to cause the denaturing of pathogenic cells
What are the benefits of fever?
increased immune response
lowers plasma iron concentration
increases the rate of reactions within the body
makes patent ill and causing them to rest
What are the two types of non-specific molecular defenses in the body?
the complement system
and interferons
what is the complement system?
20 large proteins produced by the liver
they enhance phagocytosis, inflammation, and microbe lysis
What are interferons?
small proteins vs viruses
they bind to receptors in viral cells and interfere with replication
Why are interferons considered non-specific if they target viruses?
because they target ALL viruses
What are the three specific host defenses?
Immunity
Antibodys
Antigens
What is immunity
The ability of a body to recognize infection and fight it
involves antigen-antibody reactions
What is an antibody?
Proteinaceous substances produced by the host in responce to an antigen
What is an antigen?
An anti-body generator
Any foreign substance that triggers the immune system to operate
What are the two types of immunity?
Active immunity and passive immunity
What is active immunity?
Your bod’s own immune system that produces antibodies vs infectious agnets
acquired by being exposed to disease or vaccination
What is a passive immunity?
Short term immunity to ready made antibodies
What are the three major cells of specific immunity?
B Cells (from bone marrow) T cells (from thymus) Natural Killer cells
Collectively what are these major cells called?
Where do they travel?
lymphocytes also considered WBC
in the blood to reach lymphoid organs
Where do B cells come from and what is their function?
When are the most effective?
Bone marrow
Involved in antibody mediated immunity
become plasma cells(antibody factories)
Before the microbes enter the cell
Where do t cells come from and What are their functions?
made in bone marrow matures in Thymus
Cell mediated immunity
Deals witth pathogens once they are in thr cell
What are Natural killer cells and what are their functions?
Paranodi cells
Kill malignant tumor cells and cells that are covered in antibodies
Humoral Immunity
What cells are the major player in Humoral immunity?
What is humoral immunity?
Anti-body mediated immunity
b cells
What are the three basic steps in humoral immunity?
- B cells reconize antigens through receptor sites on cell membrane
- Once reconized b cells differentate
- B cells bind to antigens
What are the two types of cells that B cells can differentiate into?
Memory cells-long term immunity
Plasma cells-produce Y shaped antibodies
What part of the antibody is unique and what is similar among all?
The arms of the antibody are unique
the body is universal
What are the 6 ways antibodies bind to antigens?
NIAOCA
Neturalization Immobilization agglutination/precip. opsonization completment activation ADCC
How do antibodies neutralize microbes?
Toxins are coated and not allowed to interact
How do microbes immobilize microbes?
They bind to the pili and to the fligella stoping the ability to adhere
What is agglutination of microbes?
promoted clumping
what is opsonization of microbes?
Antibodies bind to microbes and make it easiser to phagosize
What is complement activation?
Triggers the compliment system
What is ADCC
Anti-bodie dependent cellular cytotoxicity
binding to the antigen tags it as foregn and the NK cells come and eat it
What is Cell mediated immunity and what are the major cells involved?
T-cells attack antigens once they have bound to host cells
How is Cell mediated immunity acheived?
T-cells reconize host cells that are affected by antigen
they do this via tags on the Major Histocompatibility complex (MHC)
Abnormal cells show abnormal tags
What are the differences between MHC class one and class two
MHC-1 -Endogenous antigens
MHC-2 Exogenous
What are the two types of T cells?
T-helper cells
t-cytotoxic cells
What is a t-helper cell?
what does it do when it detects an abnormal cell?
Reconizes MHC class 2 Has a CD4 receptor site -It activates b-cells -activates macrophages -activates Tc cells
WHat is a t-cytotoxic cell?
what doe it do when it detects abnormal cells?
Has CD8 receptors
reconized MHC 1
-produces Cytotoxins to kill cells
-produces cytokines to call other immune cells
What is the role of NK cells?
they kill cells bound by antibodies kill cells without tags on MHC class 1
What is the difference between congenital and acquired immunodeficency?
One is genetic and the other is due to infection or malnutrition
What are the 4 ways microbes avoid host defenses?
1 they hide in host cells
- avoid being killed
- avoid being eaten
- survive within phagocytes
