Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
91 Cards in this Set
- Front
- Back
|
What structure allows bacteria to overcome the repelling action seen from electro charges?
|
pilli
|
|
|
What impact on disease and health results from the coating of bacteria by organized glycocalyx?
|
vaccines
|
|
|
What steps must occur for human contact with microbes to result in disease
|
more virulence factors
|
|
|
What are 4 constitutive defenses?
|
-inflammatory response
-intact barriers and secretions -phagocytosis -complement system |
|
|
What are 4 induced defenses?
|
-humoral immunity (promote adherence to phagocytes)
-cell mediated immunity (effective after entry into cell) -major immunoglobulin classes -T lymphocytes |
|
|
What 2 things work together to combat pathogens?
|
constitutive and induced defenses
|
|
|
What is virulence?
|
the relative ability of an organism to produce infection
|
|
|
What does an organism's virulence (relative ability to produce infection) depend on?
|
host defenses (i.e. normal host defenses and highly virulence, impaired host defenses and low virulence)
|
|
|
See drawing of host/pathogen/environment
|
do it
|
|
|
What is transmission and what are 2 methods of transmission?
|
-mechanism to spread infectious agent to another person or through environment
-direct or indirect |
|
|
What are 3 modalities of direct infection?
|
-direct and immediate transfer (STD's)
-exposed directly to agent -transplacental |
|
|
What are 3 modalities of indirect infection?
|
-vehicle borne (telephone, keyboard)
-vector borne -airborne |
|
|
What are 3 portals of entry for pathogens?
|
-respiratory tract
-oropharynx -soft tissue |
|
|
What are 3 things that can get into the respiratory tract?
|
airborne particles, droplets, fomites
|
|
|
What are 3 things that can get into the oropharynx?
|
airborne particles, water/food, fingers
|
|
|
What are 3 things that can get into the soft tissue?
|
injuries, insect bites, injections
|
|
|
What are 3 things that determine if infection will occur?
|
-potential pathogen
-susceptible human host -suitable port of entry |
|
|
What is one potential outcome of infection?
|
disease
|
|
|
What are 2 abilities a pathogen must have to produce disease?
|
-ability to metabolize and multiple in or on host tissues
-ability to resist host's defense mechanisms long enough to reach numbers needed to produce overt disease |
|
|
Which is more likely to cause disease, colonization or carrier state?
|
carrier state
|
|
|
What is immunoprophylaxis?
|
the introduction of active immunization through vaccines or passive immunization through antisera
|
|
|
What are 2 physical barriers?
|
-skin
-mucosa |
|
|
What are 2 local conditions of barriers/secretions?
|
-low pH on skin surface
-completing microflora |
|
|
What do mucous secretions contain and what does it do?
|
lysozyme (enzyme that hydrolyzes peptidoglycan)
|
|
|
What is the central activity of the non-specific inflammatory response?
|
phagocytosis
|
|
|
What are the main cells involved in phagocytosis?
|
neutrophils (earliest phagocytic cells, especially effective vs. bacteria)
|
|
|
Aside from neutrophils, what are 2 other cells that are important in phagocytosis and what do they do?
|
-monocytes/macrophages (MAC) line which can degrade larger bacteria and produce interferons which inhibit viral replication
-eosinophils which are important in destroying parasites |
|
|
The inflammatory response is considered the body's ______ line of defense
|
second
|
|
|
What are 4 steps of the inflammatory response?
|
-damaged tissues release histamine, increasing blood flow to the area
-histamines cause capillaries to leak, releasing phagocytes and clotting factors into the wound -phagocytes engulf bacteria, dead cells and cellular debris -platelets move out of the capillary to seal the wound |
|
|
What causes the pain involved in inflammation?
|
-stretching of tissues
|
|
|
What are 4 events involved in the inflammatory response?
|
-dilute potentially toxic agents by increasing blood flow (rubor, tumor)
-enhance phagocytosis -release inflammatory mediators -trigger complement cascade |
|
|
Phagocytosis is a 3 step process involving what?
|
-enclose target antigen in phagosome
-fuse with cytoplasmic granules -kill with oxidative burst |
|
|
What are 2 ways to enhance phagocytosis?
|
-increase the number of phagocytes
-increase recognition when non-specifically coated (opsonize=relish) |
|
|
What are 2 things that help increase the number of phagocytes?
|
-diverted by chemotactic factors (cytokines i.e. IL or TNF)
-increase capillary permeability (histamines) |
|
|
What are 2 things that increase recognition for eventual phagocytosis when pathogens are non-specifically coated?
|
-complement (innate defense capability)
-C-reactive protein (binds to bacteria surface) |
|
|
What is the relative definition of a fever?
|
greater than 100 degrees Farenheit
|
|
|
Which 2 inflammatory mediators help produce fever?
|
TNF, IL
|
|
|
Which inflammatory mediator inhibits viral protein synthesis?
|
interferon (best strategy for treating hepatitis)
|
|
|
What is the ultimate goal of the inflammatory response?
|
promote phagocytosis
|
|
|
What are 4 ways in which the complement cascade assists the inflammatory response?
|
-inflammation (C3a, C5a)
-attract phagocytes (C5a) -coat bacteria, activate phagocytes (C3b) -interact w/ MAC to cause lysis (C5b) |
|
|
What are 3 aspects involved in specific immunity?
|
-specific recognition of an antigen
-antigen-antibody complex results in attachment to specialized immune cells (complement-mediated activity, destroy via biological mediators) -antibodies confer immunity (preformed antibodies limit microbial replication) |
|
|
B cells
|
-develop in bone marrow
-part of antibody (humoral) response |
|
|
T cells
|
-develop in thymus
-cell-mediated response |
|
|
When an antigen is recognized, which cells are activated?
|
both B and T cells
|
|
|
For first time exposure to a disease, which system would go into effect?
|
non-specific immune system
|
|
|
About how long does it take for a disease state to come and go?
|
about a week
|
|
|
How many classes of B cell isotopes are there and what are they?
|
-5 classes
-IgG, IgA, IgM, IgE, IgD |
|
|
For first time exposure (primary immune response) how long is the lag to reach sufficient IgM?
|
7-10 days to reach sufficient IgM
|
|
|
For second time exposure (secondary immune response) how long is the lag to reach
|
3-5 days lag then IgG (heightened response), immunoglobulin then persists (or responsen with IgA or IgE)
|
|
|
What is half life?
|
time it takes for half of a substance to go away
|
|
|
IgM
|
5 day half life in circulation
|
|
|
IgG
|
-75% of immunoglobulin in adults (most abundant isotope)
-can cross placenta |
|
|
IgE
|
-defense vs. parasites/allergies
|
|
|
IgA
|
-predominant antibody in secretions
-important in mucosal immune system |
|
|
What is the complement?
|
overlap of inflammatory response and specific immunity
|
|
|
Complement mediated activity
|
-"complement" to humoral immunity
-opsonization to promote phagocytosis -inflammatory response enhanced |
|
|
What are 3 important mechanisms of humoral immunity?
|
-neutralize toxins and viruses (bind to prevent adherence)
-opsonize organism (promote phagocytosis) -activate complement system (opsonization and lysis) |
|
|
What are 2 characteristics of cell-mediated immunity?
|
-highly specific, discriminatory
|
|
|
What is the responsibility of cell-mediated immunity?
|
recognize foreign cells or virus-infected cells
|
|
|
What are the 2 types of T cells?
|
CD4: T helper cells
CD8: cytotoxic T cells (killer cells |
|
|
CD4 (4 things)
|
-activated by antigen binding
-role in humoral response (differentiation of B cells) -differentiate CD8 cells -release macrophage activators (cytokines) |
|
|
CD8 (2 things)
|
-once activated, recognize foreign cells or virus infected cells
-most important mechanism vs. virus |
|
|
What is the most important mechanism vs virus?
|
CD8 cells
|
|
|
What are 4 ways to generate information that will aid in identifying a pathogen?
|
-microscopic examination
-cultivation and morphology evaluation -measure pathogen specific response -detection of pathogen specific macromolecules |
|
|
For which 2 organisms is direct microscopic exam suitable?
|
-helminthic
-protozoal |
|
|
What are 2 special stains that can be used to ID morphology of bacteria?
|
-gram stain
-ab based identification |
|
|
What type of organisms grow on cell cultures?
|
obligate, intracellular pathogens (viruses, chlamydia)
|
|
|
What 2 pathogens are not suitable to be grown on a culture?
|
helminthic and protozoal
|
|
|
What does chalmydia act like?
|
virus
|
|
|
Generally, what are cultures routine for?
|
bacteria and fungi (selective media, antibiotic sensitivity)
|
|
|
What are 2 examples of antibody based identification?
|
indirect and direct
|
|
|
Indirect antibody based identification
|
-determine antibody activity via reaction
-agglutination, complement fixation |
|
|
Direct antibody based identification
|
-measure specific antibody
-enzyme linked (ELISA), indirect flourescent antibody, western blot |
|
|
Typically, titers are which immunoglobulin?
|
IgG
|
|
|
What does measurement of the pathogen-specific response depend on?
|
-development of antibody response (time delay which limits usefulness in early infection...measuring IgM fraction may be useful early)
|
|
|
What should you also look at when measuring pathogen-specific response?
|
-rise in antibody levels (convalescent compared to acute)
-four fold increase typically significant |
|
|
What are 2 tests involved in detection of pathogen-specific macromolecules?
|
antigen detection tests
nucleic acid based tests |
|
|
Antigen detection tests
|
-antibody coated latex beads
-radioimmunoassay |
|
|
Nucleic acid based tests
|
-PCR amplification (PCR makes LOTS of copies)
|
|
|
True positive
|
correctly predicts the presence of a pathogen
|
|
|
True negative
|
negative test in the absence of a pathogen
|
|
|
False positive
|
pathogen absent, test positive
|
|
|
False negative
|
pathogen present, test negative
|
|
|
Sensitivity
|
likelihood a test will be positive if the pathogen is present
|
|
|
What is the problem with highly sensitive tests?
|
false positives
|
|
|
Specificity
|
likelihood a test is negative if the pathogen is absent
|
|
|
Screening test
|
sensitive but not specific
|
|
|
Confirmatory test
|
highly specific
|
|
|
Two factors involved in "positive predictive value"
|
-test factors: specificity of 99.8% (one false positive every 500 tests)
-population factors: must be considered |
|
|
Population factors: population with low disease prevalance
|
-one case in every 500 patients
-positive more likely to be false |
|
|
Population with high disease prevalence
|
-400 cases in every 500 patients
-positive more likely to be true |
