Test 5

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Test 5
2010-07-12 18:46:33

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  1. What does it take to get an infection? What are some things required to get one?
    • Infection- a condition in which pathogenic microbes penetrate host defenses, enter tissues, adn multiply
    • 1. contact - microbes adhere to exposed body surface
    • 2. colonization with flora
    • 3. invasion - microbes cross lines of defense and enter sterile tissue
    • 4. infection - pathogenic microbes mulitply in the tissues
  2. What are other terms/words used to describe flora?
    • Most areas of the body in contact with the outside enviornment harbor resident microbes; Internal organs, tissues, and fluids are microbe-free
    • Transients - microbes that occupy the body for only short periods of time
    • Residents - microbes that become established
    • Indingenous flora
    • Microflora
    • Biota
    • Commensuals
  3. In order to get an endogenous infection, what has to occur?
    They occur when normal flora is introduced to a site that was previously sterile
  4. When do you start picking up germs? (as part of life in normal flora)
    • Uterus and contents are normally sterile and remain so until just before birth
    • Breaking of fetal membrane exposes the infant; all subsequent handling and feeding continue to introduce what will be normal flora
  5. Where can you find resident flora?
    • Skin is the largest and most accessible organ
    • 2 cutaneous populations. Transients - influences by hygiene and Resident - stable, predicatable, less influenced by hygeine.
    • Can also find in GI tract, upper respiratory tract, genital tract, urinary tract, eyes and ears
  6. What are some of the virulence factors? Examples
    • Virulence factors - traits used to invade and establish themselves in the host, also determine the degree of tissue damage that occurs, severity of disease. Any characteristic or structure of a microbe that contributes to the disease state.
    • Exoenzymes - dissolve extracellular barriers and penetrate through or between cells
    • Toxigenicity - capacity to produce toxins at the site of multiplication. 1. Endotoxin - toxin not secreted but is released after the cell is damaged. 2. Exotoxin - toxin molecule secreted by a living bacterial cell into the infected tissue
  7. Know the stages of illness. 4 Stages
    • 1. Incubation period - time from the initial contact w/ the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficent to cause symptoms; several hours to several years
    • 2. Prodromal stage - vague feelings of discomfort; nonspecific complaints
    • 3. Period of invasion - multiples at high levels, becomes well-established; more specific signs and symptoms
    • 4. Convalescent period - as person begins to respond to the infection, symptoms decline
  8. Localized infection, Secondary infection, mixed infection and acute infection?
    • 1. Localized infection - microbes enter the body and remains confined to a specific tissue
    • 2. Secondary infection - another infection by a different microbe
    • 3. Mixed infection - several microbes grow simultaneously at the infection site
    • 4. Polymicrobial
    • 5. Acute infection -comes on rapidly, with severe but short-lived effects
    • 6. Systematic infection - infection spreads to several sites and tissue fluids usually in the bloodstream
    • 7. Focal infection - when infetious agent breaks loose from a local infection and is carried to other tissues
  9. What's the definition of a sign? Symptoms?
    • Earliest symptoms of disease as a result of the activation of the body defenses. Fever, pain, soreness and swelling
    • Signs of inflammation
    • Edema - accumulation of fluid
    • Granulomas and abscesses - walled-off collections of inflammatory cells and microbes
    • Lymphadenitis - swollen lymph nodes
  10. What's a syndrome?
    When a disease can be identified or defined by a collection of signs or symptoms
  11. What are the signs of inflammation?
    • Edema - accumulation of fluid
    • Granulomas and abscesses - walled-off collections of inflammatory cells and microbes
    • Lymphadenitis - swollen lymph nodes
    • Fever, pain soreness and swelling
  12. Know what immunology is? Epidemiology is?
    • Immunology - the study of body's second and third lines of defense
    • Epidemiology - the study of the frequency and distribution of disease and health-related factors in human populations
  13. What is W.H.O?
    • World Health Organization
    • Specialized agency of the United Nations that acts as a coordinating authority on internationl public health
  14. What is CDC?
    • Center for Disease Control and Prevention
    • A Federal agency in the Dept of Health and Human Services; located in Atlanta -investigates and diagnoses and tries to control or prevent diseases
    • (esp new and unusual diseases)
  15. What is incidence rate? Prevalence rate?
    • Incidence - a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period.
    • Prevalence - which is a measure of the total number of cases of disease in a population, rather than the rate of occurrence of new cases
  16. 17. What are things like endemic, how is that different from epidemic? Or pandemic?
    • Endemic - disease that exhibits a relatively steady frequency over a long period of time in a particular geographic locale
    • Sporadic - when occasional cases are reported at irregular intervals
    • Epidemic - when prevalence of a disease is increasing beyond what is expected
    • Pandemic - epidemic across contients
  17. What is a reservoir?
    • Primary habitat of pathogen in the natural world.
    • Human or animal carrier, soil, water, plants
  18. A carrier of fomite?
    • Carrier - an individual who inconspicuously shelters a pathogen and spreads it to others; may or may not have experienced disease due to the microbe
    • Fomite - any inanimate object/substance capable of carrying infectious organisms and hence transferring them from one individual to another. It can be anything from a cloth to a mop head.
  19. Difference between carrier and vector?
    • Carrier - an individual who inconspicuously shelters a pathogen and spreads it to others; may or may not have experienced disease due to microbe
    • Vector - A live animal (other then human) that transmits an infectious agent from one host to another
  20. Whats the difference between aerosols and mechanical vectors?
    • Aerosol - airborne infectious that are caused indirectly stuff like, TB, Influenza virus, hantavirus
    • Mechanical - not necessary to the life cycle of an infectious agent and merely transports it without being infected
  21. Whats a drop of nuclei?
    • Indirect contact pattern of transmission - passes from infected host to intermediate conveyor and then to another host
    • Airborne - droplet of nuclei, aerosols
  22. What's a biological vector?
    Biological vectors - actively participate in a pathogen's life cycle
  23. Know the different ports of entry, whats the most common?
    Respiratory tract
  24. Know examples of the first line of defense
    • Skin and mucous membranes of respiratory, urogenital, eyes and digestive tracts
    • Outermost layer of skin is composed of epithelial cells compacted, cemented together and impregnated w/ keratin; few pathogens can penetrate if intact
    • Flushing effect of sweat glands
    • Damaged cells are rapidly replaced
    • Mucous coat impedes attachment and entry of bacteria
    • Blinking and tear production
    • Stomach acid
    • Nasal hair traps larger particles
  25. Know the difference between the first and second line of defense
    • First line of defense - any barrier that blocks invasion at the portal of entry - nonspecific
    • Second line of defense - protective cells and fluids; inflammation and phagocytosis - nonspecific
  26. For WBC's, know the different functions of it? Which are numerous and which are least?
    • Neutrophils - 55-90% - lobed nuclei w/ lavender granules; phagocytes
    • Eosinophils - 1-3% - orange granules and bilobed nucleus; destroy eukaryotic pathogens
    • Basophils - 0.5% - constricted nuclei, dark blue granules; release potent chemical mediators. Mast Cells: nonmotile elements bound to connective tissue
    • Lymphocytes - 20-35% - specific immunte response. B humoral immunity - activated B cells produce antibodies. T Cells - Activated T cells modulate immune functions and kill foreign cells.
    • Monocytes, macrophages - 3-7% - largest of WBC's, kidneyshaped nucleus; phagocytic
  27. What is diapedesis? What is hemopoiesis?
    • Diapedesis - migration of cells out of blood vessels into the tissues
    • Hemopoiesis - production of blood cells
  28. What are plasma cells?
    .92% water, metabolic proteisn, globulins, clotting factors, hormones, and all other chemicals and gases to support normal physiological functions
  29. What is the RES? What does it do?
    • Reticuloendothelial System: network of connective tissue fibers that interconnects other cells and meshes with the connective tissue network surrounding organs.
    • Inhabited by phagocytic cells - mononuclear phagocyte system - maacrophages ready to attack and ingest microbes that passed the first line of defense
  30. Know the different lymph organs, which ones are going to filter your blood?
    • Spleen - structurally similar to lymph node; filters circulating blood to remove worn out RBC's and pathogens
    • Thymus - high rate of growth and activity until puberty, then begins to shrink; site of T-cell maturation
    • Lymph nodes - small, encapsulated, bean-shaped organs stationed along lymphatic channels and large blood vessels of the thoracic and abdominal cavities
    • Misc - GALT, Peyers patch
  31. Inflammation, know the general properties of this
    • Classic signs and symptoms characterized by:
    • Redness - increased circulation and vaso dilation in injured tissues in response to chemical mediators and cytokines
    • Warmth - heat given off by the increased blood flow
    • Swelling - increased fluid escaping into the tissue as blood vessels dilate - edema; WBC's microbes, debris and fluid collecting to form pus; helping prevent spread of infection
    • Pain - stimulation of nerve endings
    • Possible loss of function
  32. What chemicals begin a fever response?
    • Initiated by circulating pyrogens which reset the hypothalamus to increase body temperature; signals muscles to increase heat production and vasoconstriction.
    • Exogenous pyrogens - products of infectious agents
    • Endogenous pyrogens - liberated by monocytes, neutrophils, and marcophages during phagocytosis; interleukin-1 (IL-1) and tumor necrosis factor TNF
    • Benefits of fever:
    • Inhibits multiplication of temperature - sensitive microorganisms
    • Impedes nutrition of bacteria by reducing the available iron
    • Increases metabolism and stimulates immune reactions and protective physiological processes
  33. What is the third line of defense?
    Third line of defense - acquired w/ exposure to foreign substance; produces protective antibodies creates memory cells - specific