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130 Cards in this Set
- Front
- Back
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What are the two types of host defense mechanisms?
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Innate defenses and inducible defenses.
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T/F - Innate defenses have also been referred to as "natural" or "constitutive" resistance since they are inherent to the host.
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True.
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What are normal flora?
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Bacteria and other microbes that are consistently associated with an animal.
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What is the name for a relationship where there is no apparent benefit or harm to either member of the association?
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Commensalism.
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What staph microorganism is a consistent inhabitant of human skin?
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Staphylococcus epidermidis.
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What bacteria live on the vaginal epithelium of a woman?
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Lactic acid bacteria.
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What function does lactic acid bacteria provide for it's host?
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Protects the vagina from colonization and disease caused by yeast and other microbes.
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Antibiotics are defined as substances produced by a microorganism that will what?
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Kill or inhibit other microorganisms.
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Enterococcus, Staphylococcus aureus, and Pseudomonas aeruginosa have what in common?
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All are resistant to antibiotics.
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Opportunists are bacteria that cause a disease in a what kind of host?
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Compromised, or otherwise unhealthy host.
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Pseudomonas aeruginosa is one of the most common opportunistic pathogens of humans and causes what?
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Urinary tract infections, respiratory system infections, soft tissue infections, and a variety of systemic infections particularly in cancer and AIDS patients who are immunosuppressed.
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Pathogenic bacteria are able to produce disease because they possess certain structural or biochemical or genetic traits that render them what?
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Pathogenic or virulent.
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What is the period of incubation the time between of?
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The time between the entry of the parasite into the host and appearance of symptoms.
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During what period is the disease most acute?
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The period of illness.
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During what period do the signs and symptoms of illness subside?
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Period of decline.
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What is a subclinical infection?
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The asymptomatic carrying of an infection.
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How can a subclinical infection be identified?
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By microbiological culture or a DNA technique such as polymerase chain reaction tests.
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How can communicable diseases be spread?
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Through bodily fluids, contaminated surfaces, air or food.
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Infectious pathogens include what sources?
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Viruses, bacteria fungi, protozoa, multicellular parasites, and aberrant proteins (prions).
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What term describes the ability of an organism to enter, survive and multiply in the host?
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Infectivity.
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The term "infectiousness" of a disease indicates what?
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The comparative ease with which the disease is transmitted to other hosts.
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Is an infection synonymous with an infectious disease?
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No.
Some infections do not cause illness in a host. |
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What are noncommunicable diseases?
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A disease which is not contagious.
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What are some causes of noncommunicable diseases?
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Lifestyle, genetics, or environment.
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What is the most popular cause of noncommunicable diseases?
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Lifestyle choices such as drug, alcohol or tobacco use.
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What are examples of noncommunicable diseases?
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Heart disease, cancer, asthma, diabetes, allergies, stroke, etc.
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What is a disease called that only occurs occasionally?
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Sporatic disease.
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A disease present in a population at all times is called what?
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Endemic.
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A disease that breaks out in a population in a short period is called what?
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An epidemic.
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An epidemic disease occurring throughout the world is called what?
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Pandemic.
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What are the two terms used to describe diseases that occur rapidly and last for a short time, and develop slowly and last for a long time?
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Acute is a rapid onset and short lasting disease while chronic is a slow onset and long-lasting disease.
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What is a subacute disease?
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One that has vague symptoms and lasts for a long time.
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What is a latent disease?
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A disease that remains inactive in host for a time then becomes active.
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What is secondary disease?
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One that is onset due to an opportunistic microorganism (usually a resident) that takes advantage of the suppressed immune system from the primary disease.
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What are infections acquired during a hospital stay called?
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Nosocomial infections.
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What are some examples of reasons a host in the hospital might be immunosuppressed and therefore very receptive to a nosocomial infection?
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Cancer, nutritional deficiency, burns, etc.
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A disease that remains in a population requires a source of pathogens called what?
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Reservoir of infection. This can be human, animal, or non living (such as soil).
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A person who has recovered from a disease or infection but is still shedding infectious organisms is called what?
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A carrier.
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Direct transmission of disease occurs from person to person by what?
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Touching, kissing, and sexual intercourse.
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A towel, cup, or eating utensil that is involved in disease transmission could be classified as a what?
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Fomite.
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What are vectors of transmission?
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Living things.
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What are mechanical vectors?
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Body parts that may carry pathogens on them, usually found in arthropods such as mosquitoes, flies, and ticks.
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What are vehicles of transmission?
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Lifeless objects such as food, water and air.
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How do organisms enter a new individual?
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Through a portal of entry.
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What are the most common portals of entry for a human?
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Mucous membranes, especially respiratory, gastrointestinal, and urogenital tracts, and the skin.
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What is it called when microorganisms penetrate below the skin to achieve a portal of entry?
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Parenteral route.
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What is the dose of an organism?
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The number of microorganisms required to establish an infection.
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What is the dose for typhoid fever?
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A few hundred bacteria.
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What is the dose for cholera?
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A few million bacteria.
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The dose expressed as LD50 refers to what?
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The dose of microorganisms that will kill 50% of the hosts it enters.
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What is an example of a mechanical barrier to disease?
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The skin, mucous membranes.
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What are the outermost layers of skin cells impregnated with to help protect against microorganisms?
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The insoluable protein keratin.
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How do mucous membranes protect the host against microorganisms?
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Tears, mucus, and saliva rid the membrane of irritants. Nasal hairs trap particles in the respiratory tract, and fluids exert a flushing action.
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What chemical barriers do tears and saliva contain to protect against microorganism portal of entry?
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Lysozyme which breaks down the peptidoglycan of the cell wall that gram-positive bacteria have.
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What chemical barrier does the vagina have to protect it from microorganisms?
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Lactic acid.
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What chemical barrier does the stomach have to protect it from the bacteria in the intestine?
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Hydrochloric acid.
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What type of response is fever, to microorganisms?
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Nonspecific defense mechanism.
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What is the function of phagocytosis?
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To engulf and destroy the microorganisms of disease.
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What are two types of phagocytes that circulate white blood cells?
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Neutrophils and monocytes.
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Monocytes in the body's tissues are transformed into phagocytes called what?
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Macrophages.
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Macrophages move through the tissues of the body performing phagocytosis and destroying mainly what?
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Parasites.
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What system are macrophages part of?
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Reticuloendothelial system.
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The microbial debris from a cell is eliminated in the process of what?
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Egestion.
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The protein molecules that bind to microorganisms and encourage engulfing by phagocytosis is called what?
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Antibodies.
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Inflammation mobilizes components of the immune system, sits into motion repair systems, and encourages what?
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Phagocytes to come to the area and destroy any microorganisms present.
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Cytokines are chemical substances that can control what?
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Inflammation.
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The loss of fluid leads to a local swelling called what?
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Edema.
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The immune system enables the body to recognize a foreign agent as what?
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Nonself.
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Immune responses are directed at a series of foreign substances known as what?
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Antigens, or immunogens.
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Are most antigens high in molecular weight or low in molecular weight?
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Most antigens are high molecular weight substances.
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Antigenic determinants that decide if a substance requires an immune response are called what?
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Epitopes.
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What substances usually compose an antigenic determinant?
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Monosaccharide units of a polysaccharide, or several amino acids of a protein molecule.
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Autoantigens are what?
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A person's own self antigen.
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Alloantigens are what?
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Antigens found in different members of the same species.
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What are the two major branches of the immune system?
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Antibody-mediated (humoral) and cell-mediated immunity.
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Cells of the immune system are associated with what system?
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The lymphatic system.
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Lymphocytes of the lymphatic system are drived from what, and where is it found?
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Lymphocytes are derived from stem cells that are found in bone marrow.
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Stem cells produce what types of cells?
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B-lymphocytes (B-cells) and T-lymphocytes (T-cells).
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T-lymphocytes are converted in what gland?
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The thymus gland.
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Cell-mediated immunity depends on the activity of what cells?
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T-cells.
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Why don't cytotoxic T-cells produce antibody molecules?
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They leave the lymphatic tissues and enter circulation to gather at the infection site and interact directly with the offending organisms.
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How do the T-lymphocytes interact with virus-infected and bacteria-infected cells?
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By exerting a "lethal hit" on the cells and secreting substances into them that lead to cellular destruction.
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When T-cells directly interact with virus or bacteria-infected cells, they also secrete substances called lymphokines. What is their purpose?
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Lymphokines attract phagocytes to the area and encourage them to perform phagocytosis on the infected cells, which helps relieve infection.
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What microorganism composes the complement system?
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Proteins.
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How does the complement system work?
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A series of proteins circulate in the blood and encourage phagocytosis. The complement system is stimulated by many immune reactions.
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The descriptive term for how the complement system operates is what?
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It operates in a cascade of reactions.
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What are the two pathways for complement activity?
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The classical pathway and alternative pathway.
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What does the classical pathway of the complement system operate with?
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The highly specific immune system and is initiated by antibodies uniting with antigens.
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What does the alternative pathway of the complement system operate with?
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It is nonspecific and initiated by tumors, cell wall components of bacteria, and various microorganisms.
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What is another name for the alternative pathway?
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The properdin pathway because properdin is one of the proteins operating in it.
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Which one is slower: the classical or alternative pathway of the complement system?
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The alternative (or properdin) pathway.
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What is innate immunity?
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Immunity present from birth.
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Acquired immunity is derived from activity of what?
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The immune system.
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What two parts is acquired immunity divided into?
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Active and passive immunity.
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Active immunity is acquired when the body produces what?
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Antibodies.
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Can active immunity be natural, artificial, or both?
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Active immunity can be both natural and artificial.
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Passive immunity comes about when the body receives antibodies from where?
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An outside source.
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Does the immune system operate in passive immunity?
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No, but it does protect instantaneously.
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Can passive immunity be natural, artificial, or both?
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Passive immunity can be both natural and artificial.
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When does naturally acquired active immunity occur?
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When a person produces antibodies during an illness even though the disease does not occur.
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Artificially acquired active immunity occurs when?
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When a person produces antibodies after exposure to a vaccine.
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Naturally acquired passive immunity develops when?
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When antibodies pass from a mother to her child across the placental lining.
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Newborns are born with which: IgG or IgA?
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IgG. They will receive IgA if breast-fed.
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Artificially acquired passive immunity is what?
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When a person is given an injection of antibodies (usually IgG). They remain for a period of several days or weeks then disappear.
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What is artificially acquired passive immunity given for?
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To protect people who have been exposed to tetanus, diptheria or botulism.
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What are radioimmunoassays used for?
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Measure concentrations of antigens (i.e. hormone levels in the blood) by the use of antibodies.
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What is the difference between a radioimmunoassay and the ELISA method?
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The ELISA method measures the antigen-antibody using colorimetric signals instead of a radioactive signal.
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Preciptiation is a type of serological test where precipitins react with dissolved antigens and form large complexes that become visible as a fine precipitate. What is this test performed in?
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Fluid or gel.
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The fluorescent antibody test technique is a serological test that helps make visible what?
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An antigen-antibody reaction.
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How is a positive reaction signaled in a fluorescent antibody test?
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Fluorescent dye accumulates on the surface.
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Enzyme immunoassays or enzyme-linked immunosorbentassay tests are called what?
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ELISA.
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An ELISA test proves positive when a what is added on enzyme accumulation and the molecules change color?
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Substrate.
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Monoclonal antibodies can be purified and used for diagnostic purposes as well as carriers for toxic compounds that could be used to what?
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Kill tumor cells in the body if antitumor drugs are carried.
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What is polymerase chain reaction (or PCR) used for?
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Generating thousands to millions of copies of a particular DNA sequence.
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The polymerase chain reaction method relies on what (the repeated heating and cooling of the reaction) for DNA melting and enzymatic replication of the DNA?
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Thermal cycling.
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What are the short DNA fragments containing sequences complementary to the targeted region that are key components to enable replication called?
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Primers.
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What is gene probe?
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Gene probe is a specific segment of single-strand DNA that is complementary to a desired gene.
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In genetic coding what are the opposites of A and C?
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G and T.
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When does injury resulting from hypersensitivities develop, before or after an interaction has taken place between antigens and antiboides?
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After an interaction has taken place.
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What type is anaphylactic hypersensitivity classified as?
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Type I.
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When antibodies are involved the reactions fall under the heading of what kind of hypersensitivity?
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Immediate hypersensitivity.
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When T-lymphocytes are involved the reactions are characterized as what kind of hypersensitivity?
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Delayed hypersensitivity.
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Immediate hypersensitive reactions include what?
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Anaphylaxis, allergic reactions, cytotoxic reactions, and immune complex reactions.
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Delayed hypersensitive reactions are characterized as what?
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Contact dermatitis or infection allergy.
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If antigens are introduced directly into the tissues, such as by insect sting or injection, the result is a systemic reaction such as what?
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Anaphylactic shock.
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Antigens eliciting an immediate hypersensitivity are called what?
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Allergens.
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When the contact is a superficial one involving epithelial tissues the reaction is more localized and called what?
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An allergy or atopy?
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In anaphylaxis the allergens are introduced to the body directly to the tissues in a concentrated or diluted form?
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Concentrated.
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The decreased ability of the B-lymphocytes to produce antibodies is called what?
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Hypogammaglobulinemia.
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A reduced capacity for cell-mediated immunity due to abnormalities of the T-lymphocytes is called what?
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DiGeorge's syndrome.
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