208 final – Microbiology – Flashcards
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| the area in which a microorganism enters the body. They may be cuts, lesions, injection sites, or natural body orifices. |
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| portals of entry |
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| LD 50 |
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| lethal dose for 50% of hosts |
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| ID 50 |
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| species and strain specific, amount of invading organisms needed to cause disease in 50% of hosts |
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| LD 50 must be ___ than ID 50 |
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| greater |
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| ligands/attachment proteins |
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| adhesins |
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| other factors that can allow infectious disease to adhere |
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| fimbriae, capsules, and biofilms |
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| Enzymes, toxins, and other factors that affect the relative ability of a pathogen to infect and cause disease. |
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| virulence factors |
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| describe exotoxins |
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| -produced inside bacteria and released out of cell -proteins -relatively easy to make food safe when the food contains exotoxins -susceptible to heat -botulinum toxin -diphtheria toxin -tetanus -mostly gram +, but some gram - -very toxic |
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| describe endotoxins |
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| -cell bound -lipid based toxins -not heat susceptible -mostly gram negative -pyrogens: fever producing -weak but fatal in large doses |
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| -secreted toxin takin in by host -fluid loss in cells -proteus |
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| enterotoxins |
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| investigating a disease outbreak; look at the person, place, time, type of disorder, etc |
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| epidemiology |
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| In industrialized countries, 3/4 of the deaths are due to ____ |
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| cardiovascular disease or cancer |
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| in developing countries; ___ cause about half the death |
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| infectious agents and parasitic diseases |
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| physical barriers, chemical barriers, cellular defenses, inflammation, fever, and molecular defenses are examples of___ |
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| nonspecific defense mechanisms |
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| the first line of defense against infectious diseases is to ____ |
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| prevent bacteria from invading in the first place |
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| ___ is a physical barrier to infection; ___ is also inhabited by bacteria that inhibit the growth of other bacteria. |
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| skin; skin |
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| these produce sebum which discourages bacterial growth |
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| sebacceous glands |
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| lowers pH; inhibits bacterial growth |
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| sweat glands |
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| these block penetration of microbes and secrete mucous |
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| mucous membranes |
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| mucous secreted contains ___ & ___ |
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| glycoproteins; electrolytes |
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| ___ are cells that produce mucous |
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| goblet cells |
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| mucous forms a ___ layer and prevents __ & __ of mucous membranes. |
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| protective; drying; cracking |
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| mucous traps ___ |
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| pathogens |
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| other body defenses |
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| tears, ciliated epithelium hairs in nose, cough reflex, epiglottis |
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| second line of defenses = |
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| cellular defenses; defensive cells such as white blood cells, red blood cells, and platelets |
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| granulocytes include |
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| basophils, mast cells, neutrophils, eosinophils |
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| histamine releasing cells |
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| basophils |
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| produced in large #s in response to allergies |
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| mast cells |
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| __ & __ are types of phagocytes |
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| neutrophils & eosinophils |
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| agranulocytes include ___ & ___; they are phagocytic cells |
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| monocytes and lymphocytes |
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| what are the 4 steps in phagocytosis |
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| 1. chemotaxis 2. adherence 3. ingestion 4. digestion |
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| a body's defensive response of tissue damage from microbial infection, also responses to physical damage. |
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| inflammation |
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| inflammatory process (4 steps) |
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| 1. histamine released by basophils 2. diffuses into capillaries causing vasodilation 3. This increases blood flow to injury site. 4. blood delivers clotting factors; nutrients |
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| this raises body temp above optimum growing temp for many pathogens |
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| fever |
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| ___ increases heat which increases rate of reactions; especially in pathogenic cells |
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| fever |
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| ___ makes you feel ill; therefore you rest and prevent further damage |
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| fever |
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| molecular defenses in the complement system _____ |
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| participate in the lysis of foreign substances |
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| interferons are ____ |
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| antiviral proteins |
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| describe how interferons work between host cell 1 and host cell 2 |
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| host cell 1: makes interferon, is killed by virus host cell 2: protected against virus by interferon made by cell 1 |
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| ___ are protein molecules released by host cells to non-specifically inhibit the spread of viral infections. |
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| interferons |
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| ___ provides an effective barrier against penetration by disease agents and inhibits and destroys organisms that gain access to host tissues |
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| immunity |
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| two types of immune responses |
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| 1. humoral immune response 2. cell-mediated response |
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| two main characteristics of the immune system |
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| 1. antigen 2. antibodies |
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| ___ is a chemical that elicits an antibody response and can combine with that specific antibody |
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| antigen |
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| explain antibodies |
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| -protein -produced in response to the presence of an antigen -proteins are called immunoglobulins -basic structure: 2 heavy chains and 2 light chains - variable regions confer specificity - chains are held together by disulfide bridges |
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| what are the 4 different types of antibodies |
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| 1. IGG 2. IGA 3. IGM 4. IGE |
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| 75-80% of immunoglobulins in the system are ___ |
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| IGG |
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| ___ exist as monomers and dimers; they are the antibodies that are passed from mother to child during breastfeeding for the first few days after birth |
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| IGA |
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| ___ are commonly found in the lymph system; they tend to be first produced in response to infection |
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| IGMs |
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| ___ are monomers and we are not quite sure what they do |
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| IGGs |
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| explain the humoral immune response |
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| -antibodies dissolved in extracellular fluid -B lymphocytes (B cells) -lymphoid follicles - appendix, tonsils, and spleen |
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| ___ are stimulated by the presence of an antigen |
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| B cells |
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| B cells, as a result of being stimulated by an antigen, differentiate into ___ and ___ |
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| plasma cells; memory cells |
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| ___ cells then produce antibodies that are specific to the antigen that triggered the whole process |
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| plasma cells |
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| ___ cells are cells that retain the memory of the antigen and the type of antibody that needed to be produced |
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| memory cells |
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| explain the cell mediated response |
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| - T cells - no antibodies secreted - antigen receptors on cells - destroys bacteria and viruses within host cells - cytokines |
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| T cells differentiate into ___ and ____ cells |
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| T helper cells; T cytotoxic cells |
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| cells involved in triggering the immune destruction of tagged cells; they are necessary for B cell activation |
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| T helper cells |
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| Tc cells _____ |
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| kill infected cells |
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| NK cells are ____ |
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| natural killer cells; they kill cells infected by virus/cause apoprosis |
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| what are the target of the AIDS virus? |
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| T helper cells |
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| the second exposure elicits a ___ and ___ immune response |
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| greater; faster |
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| _ = serum _ = breastmilk _ = allergic reactions _ = initial type of antibodies produced |
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| IgG IgA IgE IgM |
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| it takes about ___ before you are exposed to something before the first antibodies show up; it takes nearly __ before large quantities of immunoglobulins show up |
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| 5 days; 2 weeks |
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| 4 types of acquired immunity |
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| 1) naturally acquired active immunity 2) naturally acquired passive immunity 3) artificially acquired active immunity 4) artificially acquired passive immunity |
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| how does one gain naturally acquired active immunity? |
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| direct exposure (directly exposed to antigen and body produced and memorized antibody) |
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| naturally acquired passive immunity example |
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| newborns and mothers breastmilk (babies acquire immunity from mothers breastmilk) |
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| artificially acquired active immunity? |
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| vaccination to receive antigen |
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| artificially acquired passive immunity |
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| receive antibodies/antitoxins which work for a temporary amount of time |
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| some vaccines involve live antigens, such as the ___, though they are usually weakended. inactive vaccines include ___. |
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| sabin polio; salk polio |
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| in a ___ you are actually given antibodies to the toxin |
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| toxoid vaccine (tetanus) |
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| ___ is used against venom |
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| antiserum (passive antibodies) |
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| Elisa direct test, tests for ___ |
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| presence of antigen in system; if antigen is present it will bind to antibody |
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| Elisa indirect test, tests for ... |
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| the presence of the antibody in the system |
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| immunological disorders/concerns |
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| -hypersensitivities -allergies -autoimmune disease - tissue matching - ABO blood grouping/hemolytic disease of newborn |
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| type I hypersensitivities |
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| -asthma, hay fever, hives - immune system overreacts and produces a large number of IgE - histamine release; histamine causes swelling by vasodilation; swelling of tissues - anaphylactic shock if extreme |
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| type II hypersensitivities |
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| - cells destroyed - blood typing - hemolytic disease of the newborn - donors antigens with recipients antibodies |
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| what antigens and antibodies does each blood type contain |
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| Blood type Antigen Antibody A A B B B A AB A+B - O - A+B |
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| A type blood can be given to ___; and can receive ___ |
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| anybody that does not have A antibodies so A and AB; from A or O |
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| B type blood can be given to ___; and can receive ___ |
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| anybody that does not have B antibodies so B and AB; from B or O |
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| AB blood type can donate to ___; and can receive ____ |
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| AB only; universal recipient and can receive all blood types |
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| blood type O can receive from ___; and donate to ___ |
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| blood type O only; universal donor and can donate to all |
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| blood can either be __ or ___ |
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| Rhesus + or Rhesus - |
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| if mother and newborn child are both RH-, then ___ |
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| no problem |
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| if child Rh + and mom Rh -, then ___ |
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| the mothers body starts to produce antibodies against the fetus; child does not suffer ill effects against this; if another Rh+ fetus comes along then the mothers body will attack the fetus |
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| most immune disorders are some sort of ___ |
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| hypersensitivities |
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| type III hypersensitivities |
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| - immune complex formed, from complement activation, later will release chemicals that cause damage - kidney and lung damage |
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| type IV hypersensitivities |
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| - cell mediated hypersensitivity - delayed reactions - happens with tissue grafts |
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| autograft |
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| tissue moved to different location from another location on the body |
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| isograft |
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| Type of graft in which tissues are moved between genetically identical individuals (identical twins) |
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| allograft |
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| Type of graft in which tissues are transplanted from a donor to a genetically dissimilar recipient of the same species. |
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| xenograft |
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| graft between different species |
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| autoimmune diseases |
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| Any of a group of diseases which result when an individual begins to make autoantibodies or cytotoxic T cells against normal body components. diabetes, ms, lupus, RA |
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| commensalism |
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| one organism benefits from the relationship while the other is neither harmed nor benefited |
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| mutualism |
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| both organisms benefit from the relationship |
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| parasitism |
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| one organism benefits while the other is harmed |
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| opportunistic organisms |
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| potentially pathogenic organisms, given the right set of circumstances these organisms can become pathogenic |
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| what are 3 of the right set of cirumstances for an opportunistic organism to become a pathogen? |
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| 1. immune suppression due to flu, chemo, etc. 2. changes in normal biota due to antibiotics 3. normal biota in unusual places. ex: e coli is normally present in the digestive tract, but if it gets into the respiratory tract it could cause illness. |
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| state Koch's postulates |
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| 1. organism is always present in infected individual 2. you can isolate and grow the organism 3. innoculation leads to disease 4. can reisolate organism |
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| exceptions to kochs postulates |
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| 1. viruses or obligate intracellular parasites 2. several viruses have the same symptoms but are caused by different pathogens 3. immunity from past exposure would prevent some people from getting the disease |
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| 3 ways in which infectious diseases are classified |
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| 1. contagious 2. incidence 3. prevalence |
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| contagious |
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| easily spread from one person to another |
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| incidence |
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| the fraction of a population that contracts the disease during a particular time period (new cases) |
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| prevalence |
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| the fraction of the population that have the disease at a particular time. (new cases + people who were sick before; always greater or equal to incidence) |
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| local vs. systemic infection |
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| local = contained in a particular area or organ system systemic = spread throughout your body; much more serious than local infection |
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| bacterial systemic infection |
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| bacteremia |
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| toxic systemic infections |
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| toxemia |
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| viral systemic infection |
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| viremia |
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| primary vs. secondary infections |
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| primary: can infect a healthy individual secondary: can only infect an immunocomprimised individual. occurs as a result of primary infections. |
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| subclinical infection |
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| A subclinical infection is the asymptomatic (without apparent sign) carrying of an (infection) by an individual of an agent (microbe, intestinal parasite, or virus) that usually is a pathogen causing illness, at least in some individuals. |
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| In medicine, a disease is considered _____ if a patient is a carrier for a disease or infection but experiences no symptoms. |
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| asymptomatic |
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| reservoirs for the organisms that are causing the infection (3) |
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| 1. humans 2. animals 3. non-living objects |
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| contact transmission = prevention = |
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| contact between sick and healthy individual. prevention = isolate sick individual, wash hands |
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| vehicle transmission = prevention = |
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| = carried from one individual to another from some sort of nonliving vehicle. = sanitize clean blankets, cups, etc. |
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| vector transmission = prevention = |
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| =transferred by a living organism (animal) = eliminate vector |
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| Can there be more than one way of transmission for a particular disease |
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| yes |
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| nosocomial infections |
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| acquired within a hospital or institution |
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| 3 factors that set up a system for a nosocomial infection: |
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| 1. compromised host: come in with infections or have surgery that stresses and traumatizes the system. 2. chain of transmission: nurses spread infections from patient to patient; only factor you can really reduce 3. microorganisms in hospital environment: more pathogenic that normal/everyday microorganisms; very difficult to totally eliminate. |
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| predisposing factors |
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| anything that makes the body more susceptible to disease. ex. comprimised immune system, gender, stress, nutrition, stress, etc. |
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| development of disease: there are a number of distinct stages in a disease, give 5 |
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| 1. period of incubation 2. prodiomal period 3. period of illness 4. period of decline 5. period of convalescence |
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| period of incubation |
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| not experiencing any symptoms, but the organism is beginning to replicate |
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| prodiomal period |
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| start feeling the first effects of the organism |
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| period of illness |
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| have full blown infection, feel very sick. from here you can recover and go into convalescence or die |
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| period of decline |
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| patient feel they are getting better, but they are still immunocompromised |
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| period of convalescence |
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| essentially better but still not %100, secondary infections can still take place |
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| do organisms have stages of all different lengths and develop in different ways |
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| yes |
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| ____ may cause disease if introduced into an unusual site in the body |
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| normal bacteria flora |
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| how are we exposed to pathogens |
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| through food, water, air, drugs, and accidental exposure |
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| what are some portals of entry for a pathogen? |
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| - mucous membrane - respiratory tract (#1) - gastrointestinal tract (#2) - genitourinary tract - conjunctiva - skin - parenteral route (needle stick) |
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| adherence factors of pathogens |
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| adhesins fimbriae capsules biofilms |
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| Molecules that attach pathogens to their target cells. |
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| adhesins |
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| Sticky, proteinaceous extensions of some bacterial cells that function to adhere cells to one another and to environmental surfaces. |
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| fimbriae |
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| A slimy community of microbes growing on a surface |
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| biofilm |
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| Glycocalyx composed of repeating units of organic chemicals firmly attached to the cell surface. |
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| capsule |
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| chemical groups that give the microorganism toxic, pathogenic properties |
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| virulence agents |
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| examples of virulence agents |
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| - adhesion factors - extracellular enzymes (kinases, collagenase, coagulase) help invasion process - antiphagocytic factors (capsules, M protein, leukocidins) - toxins (exo, endo, entero) |
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| exotoxins |
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| - produced inside bacteria and released out of cell - proteins - food poisoning from foods that are not heated -susceptible to heat - mostly come from gram postive bacteria - very toxic |
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| endotoxins |
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| - cell bound - lipids (lipid A, G-, LPS) - pyrogens - fever producing - salmonella typhi - treatment = IVs to give fluids; let infection run its course - if you take antibiotics, you will kill all the pathogens releasing all the toxins in you body simultaneously - mostly come from gram negative bacteria - weak, but fatal in large doses |
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| enterotoxins |
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| - secreted toxin taken in by hosts - causes fluid loss in cells - large volumes of watery diarrhea |
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| who, what, when, where, why, how of a disease |
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| epidemiology |
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| define virulent |
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| measure of pathogenicity |
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| define infectious |
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| causes infection |
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| define pathogenic |
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| capable of producing disease |
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| in industialized countries 3/4 of deaths are due to ____ |
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| cancer and cardiovascular disease |
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| in developing regions, ___ cause 1/2 the deaths |
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| infectious agents and parasitic diseases |
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| nonspecific defense mechinisms (generic) |
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| 1st level = physical and chemical barriers 2nd level (organism has invaded system) = cellular defenses: inflammation, fever, & molecular defense) |
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| explain the 1st line of defense |
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| - prevent bacteria from invading - skin is inhabited by bacteria that inhibit the growth of other bacteria; if they were not there you would be very prone to fungal infection. - sebaceous glands produce sebum which discourages pathogen growth - sweat glands lower pH thus inhibiting pathogen growth |
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| mucous membranes |
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| - block penetration of microbes and secretes mucous - glycoproteins and electrolytes - track pathogens and prevents them from going any further - mucous produced by goblet cells - forms a protective layer - prevents drying and cracking of mucous membranes - traps pathogens |
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| list 4 other 1st line defenses |
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| - tears - ciliated epithelium - cough reflex = trying to get rid of junk in lungs (green mucus = dead bacterial cells) - epiglottis = gag reflex |
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| second line of defense |
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| - cellular defenses - defensive cells: white blood cells, red blood cells, platelets |
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| how can white blood cells/leukocytes be separated |
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| -Granulocytes: grainy look to cells when they are stained 1. basophils: histamines, inflammation 2. mast cells: allergies 3. neutrophils: phagocytes 4. eosinophils: phagocytes, allergies, worm infections -agranulocytes: lack grainy appearance 1. monocytes: phagocytic cells 2. lymphocytes: phagocytinc cells |
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| list the steps in the process of phagocytosis |
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| 1. chemotaxis: white blood cell is attracted to invader (things on surface of bacterial cell) 2. adherence to each other 3. ingestion of bacterial cell 4. digestion: vacuole fuses with lysosome, broken down material used or excreted |
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| the increased virulence of capsulated bacterial strains is due to the ___ which helps cells avoid phagocytosis |
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| capsular polysaccharide |
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| a body's defensive response to tissue damage from microbial infection, also responds to physical damage |
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| inflammation |
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| symptoms of localized infection |
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| local heat, pain, swelling, redness |
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| describe the inflammatory process |
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| - histamine released by basophils - diffuses into capillaries causing vasodilation - this increases blood flow to injury site - blood delivers clotting factors, nutrients |
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| fever |
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| -raises body temp above optimum growing temperature for many pathogens - heat increases rate of reactions for white blood cells - let low grade fever run its course - fevers make you feel ill, therefore you rest preventing further damage |
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| list 3 molecular defenses |
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| 1. complement system 2. interferons 3. antigens |
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| complement system |
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| causes lysis of bacterial cells; bacterial cells activate one protein which in turn activates more, this cascade effect causes inflammation and tagging for phagocytic direct killing |
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| interferons |
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| antiviral proteins; gene becomes activated once virus enters, releases interferon, moves to uninfected neighboring cells and tells them to turn on anti-viral proteins |
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| antigens |
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| trigger immune responses, specifically the production of antibodies |
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| immune response that provides effective barrier against penetration by disease agents and inhibits and destroys organisms that gain access to hosts tissues |
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| humoral immune response |
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| immune response after pathogen has entered cell |
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| cell-mediated response |
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| when antigens and antibodies bind, ____ |
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| the antigen is destroyed in some way |
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| antigen |
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| chemical that triggers antibody response |
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| antibodies |
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| proteins produced in response to the presence of an antigen; immunoglobulins; basic structure is 2 heavy chains and 2 light chains, quaternary structure, variable regions confer specificity |
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| toxins which are proteins are usually ___ toxins which are lipids are ____ |
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| exotoxins endotoxins |
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| antibodies can exist as __,__, ___. the part that can vary on an antibody is where it binds ____ |
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| monomers, dimers, pentamers; antigen molecules |
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| ___ is secreted in high concentration in mothers breast milk 24 hours after birth |
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| IGA |
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| ___ are produced in large concentrations during allergic reactions |
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| IGEs |
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| __/__ are produced when immune system is in the presence of an antigen |
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| IGG/IGMs |
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| antibodies can work in 3 ways |
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| 1. agglutination 2. neutralize toxins by binding them 3. WBCs will destroy cells that have antibodies attached to them |
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| explain the humoral immune system |
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| - antibodies dissolved in extracellular fluids - B lymphocytes - lymphoid follicles = produced in the appendix, tonsils, spleen - B cells are stimulated by the presence of antigen, T cells assist. B cells differentiate into: 1. plasma cells: produce and secrete antibodies specific to antigen that caused stimulation 2. memory cells: retain the memory of the antigen and what type of antibody was produced |
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| explain the cell mediated immune response |
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| - T cells - no antibodies secreted - antigen receptors on cells - destroys bacteria and viruses within host cells -cytokines - triggering of t lymphocytes, t cells differentiate into: 1. helper t cells: release cytokines which activate other cells of the immune system, necessary for B cell activation. 2. cytotoxic T cells: kill infected cells by punching holes in cells |
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| Monocytes, macrophages, and their close relatives that process antigens and activate cells of the immune system. |
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| antigen presenting cell (APC) |
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| ___; helper T cell binds to human cell and triggers it to make interleukin 1 which further stimulates T helper cell which in turn produces interleukin 2 which triggers T helper cell to continuously clone itself |
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| Antigen presenting cell (APC) |
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| T helper cells then produce ___ which stimulate __ cells and ___ cells which triggers humoral immune response |
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| cytokines; Tc; B |
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| AIDS virus targets ___ cells which are the most needed, and most vulnerable. Drugs work to ____ |
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| T helper; mutate virus DNA or block surface determinants on virus |
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| Immune response: second exposure ____. ex: if you get poison ivy more than once, then you will get the nasty rash, it will not happen the very first time you come in contact with the plant. |
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| elicits a greater and faster response |
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| the immune system is ___ |
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| interconnected |
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| naturally acquired active immunity: naturally acquired passive immunity: artificially acquired active immunity: artificially acquired pass. immunity: |
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| direct exposure newborns, breast milk vaccinations, antigens antibodies, antitoxins |
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| what is the function of a histamine |
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| a vasodilator |
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| types of immunization, vaccines: |
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| 1. active antigens - vaccinated using an attenuated pathogen, can backfire and cause disease (sabin polio) 2. inactive vaccines (salk polio) 3. toxoid vaccines (tetanus) - inactive toxin 4. passive antibodies - antiserum (against venom) |
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| How do we measure immunity |
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| with the antibody-antigen response |
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| Direct ELISA test detects ____ Indirect ELISA test detects ___ |
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| detects antigens/current infection detects antibodies/current or previous |
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| type I hypersensitivities |
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| - vasodilation - asthma - hay fever - hives - Large # of IGEs - histamine relase - possible anaphylactic shock: airways constrict due to swelling of tissues surrounding airways |
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| type 2 hypersensitivities |
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| - cells destroyed - blood typing - Rh + or - |
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| if mother is Rh - and child is Rh + |
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| problem with second child |
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| if mother is Rh + and child is Rh - |
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| no problem |
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| type 3 hypersensitivities |
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| - immune complex formed from complement activation - later will release chemicals that cause damage. - kidney and lung damage |
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| type 4 hypersensitivities |
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| - caused by exposure to antigen that stimulates immune response - poison ivy - stronger second exposure reaction due to memory cells |
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| autoimmune diseases |
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| - also involves some of the different types of hypersensitivities - body turns on itself, decides some part of it is an antigen - produce antibodies against own cells that damage them - usually an increase or decrease in hormone production - diabetes, ra, transplant rejection, lupus |
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| autograft |
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| tissue moved to different location on the body - best type to avoid rejection |
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| isograft |
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| receive graft from identical twin - should not be a risk of rejection |
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| allograft |
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| receive donated tissue from an individual not genetically identical to you but relatively similar - the closer the match, the lower the risk of rejection. |
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| xenograft |
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| graft between different species, such as pig heart valves going into humans, last resort! |
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| at the beginning of an immune system response __ is produced, but later it is mainly __ that is produced |
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| IgM, IgG |
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| descibe the structure of a virus |
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| double or single stranded DNA or RNA, capsid protein coat, optional envelope and spikes, super small |
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| naked virus |
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| no envelope |
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| capsids are ___ |
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| polymers of capsomere proteins |
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| spikes act as ___ |
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| antigens; H1N1 virus had H1 and N1 spikes |
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| virus characteristics |
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| 1. host specific 2. filterable 3. obligate intracellular parasites |
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| what is an obligate intracellular parasite |
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| Obligate intracellular parasites cannot reproduce outside their host cell, meaning that the parasite's reproduction is entirely reliant on intracellular resources. |
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| life cycle of a virus |
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| 1. attachment - specific site 2. penetration - phagocytosis 3. uncoating 4. replication 5. assembly 6. release - lysis, budding out |
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| cycle of a lysogenic virus |
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| becomes incorporated into cells genome, lag period where virus is not expressed, much harder for immune system to handle |
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| life cycle of a lytic virus |
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| kills host cell |
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| budding off |
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| viruses with envelope, does not kill host cell so it can continue to churn out additional viral particles |
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| aids targets __ cells, nosocomial infections are acquired in ___ and ___ |
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| T helper; hospitals; institutions |
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| mushrooms = |
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| toad stools |
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| yeasts are __ celled, whereas molds are ___ celled |
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| single; multi |
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| hyphal mass = |
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| mycelium, grows in soil |
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| spores = |
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| asexual and sexual |
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| nutritional adaptations of fungi |
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| - can tolerate acidic environments where bacteria cannot survive. - aerobic, grow on surface - yeasts can revert to fermentation pathways if needed - more resistant to osmotic pressure, can grown in high salt/sugar environments - can grown in low moisture - require less nitrogen than bacteria |
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| fungi are ___, only invade immunocompromised people |
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| opportunistic pathogens |
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| fungi often occur as __, especially after taking ___ |
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| secondary infections, antibiotics |
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| Fungi __ use carbon dioxide as a sole carbon source, and are therefore heterotrophs |
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| cannot |
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| treatment of fungal infections |
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| - eukaryotic cells, so you are limited in targets and dosage treatments are slow - mostly topical - works by affecting permeability of cells - most treatments are fungistatic, prevent further spread but do not kill what is already present |
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| protozoans have __ life cycles |
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| complex |
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| drugs used to treat protozoan infections generally go for the ____, cause many ___ |
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| slow kill; side effects |
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| current infectious disease threats |
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| 1. emergence of naturally hypervirulent strains such as SARS and H1N1 2. bioterrorism 3. emergence of drug resistand bacteria |
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| parasitive survival factors |
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| 1.parasites have successfully adapted to almost all environmental niches within hosts 2. parasites that are best adapted are least pathogenic 3. parasite-host relationships are typically long term/chronic |
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| by definition, all ___ injure their hosts |
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| parasites |
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| the study of the cause of a disease |
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| etiology |
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| Study of the occurrence, distribution, and spread of disease in humans. |
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| epidemiology |
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| the ability of a microorganism to cause disease is termed ___, and the degree is termed ___ |
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| pathogenicity; virulence |
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| ___, also called lipid A, is released when the bacterial cells die naturally or are digested by phagocytic cells such as macrophages |
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| endotoxins |
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| many organisms secrete __ that are central to their pathogenicity in that they destroy host cells or interfere with metabolism. what are the three types? |
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| exotoxins; 1. cytotoxins 2. neurotoxins 3. enterotoxins |
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| diseases that spread naturally from their usual animal hosts to humans are called ___ |
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| zoonotic diseases |
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| if a disease develops rapidly but lasts only a short time, it is called an ___ |
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| acute disease |
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| ___ diseases develop slowly and are continual or recurrent |
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| chronic |
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| ___ diseases are those in which a pathogen remain inactive for a long period of time before becoming active. |
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| latent |
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| when an infectious disease comes from another infected host, either directly or indirectly, it is ___ |
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| communicable |
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| if a communicable disease is easily transmitted between hosts, it is also called a ___ disease |
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| contagious |
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| ___ diseases arise outside of hosts or from normal microbiota |
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| noncommunicable |
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| ___ are a subset of nosocomial infections that ironically are the direct result of modern medical procedures such as the use of catheters, invasive procedures, and surgery. |
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| iatrogenic infection |
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| the first and second lines of the bodys defenses are ___ |
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| nonspecific |
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| 5 steps of phagocytosis |
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| 1) chemotaxis 2) adherence 3) ingestion 4) killing 5) elimination |
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| ___ is movement of a cell either toward a chemical stimulus or away from a chemical stimulus |
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| chemotaxis |
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| The coating of pathogens by proteins called opsonins, making them more vulnerable to phagocytes. |
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| opsonization |
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| an encompassed pathogen by a phagocyte is known as a __ |
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| phagosome |
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| lysosomes within the phagocyte fuse with newly formed phagosomes to form ___, or digestive vesicles |
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| phagolysosomes |
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| Set of blood plasma proteins that act as chemotactic attractants, trigger inflammation and fever, and ultimately effect the destruction of foreign cells. |
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| complement system |
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| Protein molecules that inhibit the spread of viral infections. |
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| interferons |
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| the bodys ability to recognize and defend itself against distinct invaders and their products |
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| adaptive or specific immunity |
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| Cell suicide |
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| apoptosis |
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| Any immune response against a foreign antigen that is exaggerated beyond the norm. |
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| hypersensitivity |
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| Any of a group of diseases which result when an individual begins to make autoantibodies or cytotoxic T cells against normal body components. |
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| autoimmune disease |
