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Micro 13-17

Chemotherapy Term coined by Paul Ehrlich; Describes the use of chemical substances to kill pathogenic organisms w/out injuring the host.
Antimicrobial Agents A special group of chemotherapeutic agents used to treat diseases caused by microbes.
Antibiosis Means "against life."
Antibiotic A chemical substance produced by microorganisms which has the capacity to inhibit the growth of bacteria and even destroy bacteria and other microorganisms in dilute solutions.
Gerhard Domagk Discovered that prontosil, a red dye, inhibits growth of many Gram-positive bacteria.
Alexander Fleming Reasoned that the ability of the mold Penicillium to inhibit growth of microorganisms might be exploited.
Ernst Chain & Howard Florey Isolated penicillin and worked w/ other researchers to develop methods of mass production.
Selective Toxicity It must harm the microbes w/out causing significant damage to the host.
Toxic dosage level Causes host damage.
Therapeutic dosage level Successfully eliminates the pathogenic organism if the level is maintained over a period of time.
Broad spectrum Agents that are effective against a great number of microorganisms from a wide range of taxonomic groups, including both Gram-positive and Gram-negative bacteria.
Narrow spectrum Agents that are effective against only a small number of microorganisms or a single taxonomic group.
Broad spectrum drug Especially useful when a patient is seriously ill w/ an infection caused by an unidentified organism. Using such a drug increases the chance that the organism will be susceptible to it.
Narrow spectrum Used when the identity of the organism in known. Using such a drug minimizes the destruction of the host's microflora, or normal flora
Synergism Two antibiotics can be administered simultaneously so that they can exert an additive effect.
Antagonism A decreased effect can be observed when bacteriostatic drugs such as tetracycline's, which inhibit growth, are combined w/ bactericidal penicillin's, which require growth to be effective.
Interferon Cells infected w/ viruses produce one or more proteins.
Pathogen Parasite capable of causing disease in the host.
Mutualism Both members of the association living together benefit from the relationship.
Parasitism One organism, the parasite, benefits from the relationship, whereas the other organism, the host, is harmed by it.
Commensalism Two species live together in a relationship such that one benefits and the other one neither benefits nor is harmed.
Antagonism Both species harm each other w/out either benefiting.
Contamination Microorganisms are present.
Infection The multiplication of any parasitic organism w/in or on the host's body.
Disease A disturbance in the state of health wherein the body cannot carry out all its normal functions. (Disruption in homeostasis).
Pathogenicity The capacity to produce disease.
Virulence The Intensity of the disease produced by pathogens, and it varies among different microbial species.
Normal microflora Organisms that live on or in the body but do not cause disease.
Resident microflora Comprise microbes that are always present on or in the human body.
Transient microflora Microorganisms that can be present under certain conditions in any of the locations where resident microflora are found.
Locations of resident microflora: Conjunctiva; Nasal mucosa; Oral mucosa; Pharynx; Skin; Large intestine (colon); Rectum; Urethra; Vagina
Major Normal Microflora of the Human Body: Skin; Mouth; Upper Respiratory Tract; Intestine; Urogenital Tract
Opportunists Organisms take advantage of particular opportunities to cause disease.
Infectious disease Diseases caused by infectious agents such as bacteria, viruses, fungi, protozoa, and helminthes.
Inherited diseases Are caused by errors in genetic information. These may be caused by abnormalities in the number and distribution of chromosomes or by the interaction of genetic and environmental factors.
Congenital diseases Are structural and functional defects present at birth. These are caused by drugs, excessive X-ray exposure, or certain infections.
Degenerative diseases Are disorders that develop in one or more body systems as aging occurs.
Nutritional deficiency diseases Lower resistance to infectious diseases and contribute to the severity of infections.
Endocrine diseases Are due to excesses or deficiencies of hormones.
Mental disease Can be caused by a variety of factors, including those of an emotional, or psychogenic nature, as well as, certain infections.
Immunological diseases Diseases such as allergies, autoimmune diseases, and immunodeficiencies are caused by the malfunction of the immune system.
Neoplastic diseases Involve abnormal cell growth that leads to the formation of various types of generally harmless or cancerous growths or tumors.
Latrogenic diseases Are caused by medical procedures and/or treatments. Ex: surgical errors; drug reactions; infections acquired from hospital treatment (nosocomial infections).
Idiopathic diseases Are diseases whose cause is unknown.
Cytopathic effect (CPE) Viruses cause observable changes.
Cytocidal viruses Can kill cells by causing enzymes from cellular lysosomes to be released or by diverting the host cell's synthetic processes, thereby stopping the synthesis of host proteins and other essential macromolecules.
Productive infection Occurs when viruses enter a cell and produce infectious offspring.
Abortive infection Occurs when viruses enter a cell but are unable to express all their genes to make infectious offspring.
Inapparent infection (subclinical) An infection w/ signs and symptoms too mild to be recognized, except by special tests.
Stages of Infectious Disease Incubation period; prodromal phase; invasive phase; decline phase; convalescence period
Incubation period Is the time between infection and the appearance of signs and symptoms.
Prodromal phase Is a short period during which nonspecific, often mild, symptoms such a malaise and headache sometimes appear.
Prodrome Is a symptom indicating the onset of a disease.
Invasive phase Is the period during which the individual experiences the typical signs and symptoms of the disease. These may include fever, nausea, headache, rash, and swollen lymph nodes.
Acme Signs and symptoms reach their greatest intensity.
Fulminating Sudden and sever (ex. meningitis).
Decline phase The period of illness during which host defenses and the effects of treatment finally overcome the pathogen; symptoms begin to subside.
Convalescence period Tissues are repaired, healing takes place, and the body regains strength and recovers.
Epidemiology Is the study of factors and mechanisms involved in the frequency and spread of disease.
Incidence Is the number of NEW cases contracted w/in a set population during a specific period of time. (100,000 people per year).
Prevalence Is the TOTAL number of people infected w/in the population at any time.
Morbidity rate Is the number of individuals AFFECTED by a disease during a set period in relation to the total number in the population.
Mortality rate Is the number of DEATHS due to a disease in a population during a specific period in relation to the total population.
Endemic If it is present continually in the population of a particular geographic area but both the number of reported cases and the severity of the disease remain too low to constitute a public heath problem.
Epidemic Arises when a disease suddenly has a higher-than-normal incidence in a population.
Pandemic Occurs when an epidemic spreads worldwide.
Sporadic disease Occurs in a random and unpredictable manner, involving several isolated cases that pose no great threat to the population as a whole.
Common-source outbreak Is an epidemic that arises from contact with contaminated substances. The can usually be traced to a water supply contaminated with fecal material or to improperly handled food.
Propagated epidemic Arises from direct person-to-person contacts (horizontal transmission).
Epidemiologic study Collecting frequency data and drawing conclusions.
John Snow British physician; In 1854 investigated the cause of a cholera epidemic sweeping through London; proved that people became infected by drinking water contaminated with human feces.
Descriptive study is concerned w/ the physical aspects of an existing disease & disease spread. Such a study records (1) the number of cases of a disease, (2) those segments of the population that were affected, & (3) the locations and time period of the cases.
Index case The first case of the disease to be identified.
Analytical study Focuses on establishing cause-and-effect relationships in the occurrence of diseases in populations. Such studies can be retrospective or prospective.
Retrospective study Takes into account factors that preceded an epidemic. Ex: investigator might ask patients where they had been and what they had done in the month or so before they became ill.
Prospective study Considers factors that occur as an epidemic spreads. Ex: children in a population get chickenpox, at what age, and under what living conditions.
Experimental study Designs experiments to test a hypothesis, often about the value of a particular treatment.
Placebo Is a nonmedical substance that has no effect on the recipient but that the recipient believes is a treatment.
Reservoirs of infections Sites in which organisms can persist and maintain their ability to infect are essential for new human infections to occur; Ex: humans, other animals (including insects), plants, and certain nonliving materials, such as water and soil.
Carriers Individuals who harbor an infectious agent w/out having any observable clinical signs or symptoms (are also important reservoirs).
Communicable Infections can be transmitted during the incubation period (before symptoms are apparent).
Chronic carrier Is a reservoir of infection for a long time after he or she has recovered from a disease.
Intermittent carrier Periodically releases infectious organisms.
Zoonoses Diseases that can be transmitted under natural conditions to humans from other vertebrate animals. Ex: rabies is the greatest threat in the USA.
Rabies Animals infected: Dogs, cats, bats, skunks, & wolves; Modes of transmission: Bites, infectious saliva in wounds, and aerosols
Nonliving reservoirs Soil and water.
Portals of entry Sites at which microorganisms can enter the body.
Portals of exit Sites where organisms leave the body.
Contact transmission Can be direct, indirect, or by droplets.
Direct contact transmission Requires body contact b/w individuals; can be horizontal or vertical.
Horizontal transmission Individuals pass pathogens by shaking hands, kissing, touching sores, or having sexual contact.
Direct fecal-oral transmission Pathogens from fecal matter also can be spread by unwashed hands to the mouth.
Indirect contact transmission Occurs through fomites-nonliving objects that can harbor and transmit an infectious agent. Ex: soiled handkerchiefs, dishes, eating utensils, doorknobs, toys, bar soap, & money.
Droplet transmission Occurs when a person coughs, sneezes, or speak near others.
Droplet nuclei Consist of dried mucus, which protects microorganisms embedded in it.
Vehicle Is a nonliving carrier of an infectious agent from its reservoir to a susceptible host. Ex: water, air, food.
Indirect fecal-oral transmission Occurs when pathogens from feces of one organisms infect another organism.
Aerosol Is a cloud of tiny water droplets or fine solid particles suspended in air.
Foodborne Transmission Pathogens are most likely to be transmitted in foods that are inspected improperly, processed unsanitarily, cooked incompletely, or refrigerated poorly.
Vectors Are living organisms that transmit disease to humans; most are arthropods such as ticks, flies, fleas, lice, and mosquitoes.
Herd immunity (group immunity) Is the proportion of individuals in a community or population who are immune to a particular disease.
Isolation A patient w/ a communicable disease is prevented from having contact w/ the general population.
Quarantine Is the separation of "healthy" human or animal carriers from the general population when they have been exposed to a communicable disease; prevents the spread of disease during its incubation period.
Quarantine differs from Isolation in (2) ways: (1) It is applied to healthy people who were exposed to disease during the incubation period, and (2) it pertains to limiting the movements of such people and not necessarily to precautions during treatment.
Large scale immunization programs Are an extremely effective means of controlling communicable diseases for which safe vaccines are available.
Vector control Is an effective means of controlling infectious disease if the vector, such as an insect or rodent, can be identified and its habitat, breeding habits, and feeding behavior determined.
CDC Centers for Disease Control and Prevention; located in Atlanta, GA; major responsibilities for the control and prevention of infectious diseases and other preventable conditions.
WHO World Health Organization; international agency based in Geneva, Switzerland; coordinates and sets up programs to improve health in more than 100 member countries.
Nosocomial infection Is an infection acquired in a hospital or other medical facility.
Exogenous infections Are caused by organisms that enter the patient from the environment.
Endogenous infections Are caused by opportunists among the patient's own normal microflora; opportunists are most likely to cause infection if the patient has lowered resistance or if normal microflora that compete w/ pathogens have been eliminated by antibiotics.
Adaptive defenses Respond to particular agents called antigens. Viruses and pathogenic bacteria have molecules in or on them which serve as antigens. Respond to these antigens by producing protein antibodies.
Innate defenses Those that act against any type of invading agent.
Phagocytosis Cell-eating; digest and generally destroy invading microbes and foreign particles.
Stages of Phagocytosis (1) Chemotaxis; (2) Adherence; (3) Ingestion; (4) Digestion; (5) Excretion
Lymphatic system Is closely associated w/ the cardiovascular system, consists of a network of vessels, nodes, and other lymphatic tissues, and the fluid lymph.
Lymph What the fluid is called once it is in the lymphatic capillaries.
Lymph nodes As fluid moves through the vessels, it will pass through these.
B lymphocytes (B cells) Differentiate in the bone marrow itself and migrate to the lymph nodes and spleen.
T lymphocytes (T cells) Immature cells from the bone marrow migrate to the thymus, where they mature; they then migrate to the lymph nodes or spleen.
Spleen Located in the upper left quadrant of the abdominal cavity, is the largest of the lymphatic organs (filters blood).
Route of lymph flow through a lymph node: Afferent lymphatic vessel (toward); Subcapsular sinus; Trabecular sinus; Medullary sinus; Efferent lymphatic vessel (exit)
Immunity Refers to the ability of an organism to recognize and defend itself against infectious agents.
Innate immunity (genetic immunity) Exists because of genetically determined characteristics.
Adaptive immunity (acquired immunity) Immunity obtained in some manner other than by hereditary.
Naturally acquired adaptive immunity Is most often obtained by having a specific disease.
Artificially acquired adaptive immunity Is obtained by receiving an antigen by the injection of vaccine or immune serum that produces immunity.
Active immunity Is created when the person's own immune system activates T cells, or produces antibodies or other defenses against an infectious agent.
Naturally acquired active immunity Is produced when a person is exposed to an infectious agent.
Artificially acquired active immunity Is produced when a person is exposed to a vaccine containing live, weakened, or dead organisms or their toxins.
Passive immunity Is created when ready-made antibodies are introduced into the body.
Naturally acquired passive immunity Is produced when antibodies made by the mother's immune system are transferred to her offspring; breastfeeding
Artificially acquired passive immunity Is produced when antibodies made by other hosts are introduced into a new host; Ex: a person who is bitten by a rattlesnake may receive snake antivenin injection.
Antigen Is a substance the body identifies as foreign and toward which it mounts an immune response-often it is also referred to as an immunogen. (Humoral)
Hapten Small molecules can act as an antigen if it bonds to a larger protein molecule.
Titer Is the quantity of a substance needed to produce a given reaction.
Natural killer cells (NK cells) Nonspecifically kill cancer cells and cells infected w/ viruses, w/out having to utilize the specific immune responses.
Apoptosis Other molecules enter the target cell and fragment its nuclear DNA (programmed cell death).
Humoral immunity Is carried out by antibodies circulating in the blood.
Recognition of self versus nonself The ability of the immune system to tolerate host tissues while recognizing and destroying foreign substances, probably due to the destruction (deletion) of clones of lymphocytes during embryonic development.
Specificity The ability of the immune system to react in a different and particular way to each foreign substance.
Heterogeneity The ability of the immune system to respond in a specific way to a great variety of different foreign antigens.
Memory The ability of the immune system to recognize and quickly respond to foreign substances to which it has previously responded.
IgG The main class of antibodies found in the blood, accounts for as much as 20% of all plasma proteins; Is produced in largest quantities during a secondary response.
IgA Occurs in small amounts in blood and in larger amounts in body secretions such as tears, milk, saliva, and mucus and attached to the lining of the digestive respiratory, and genitourinary systems.
IgM Is found as a monomer on the surface of B cells and is secreted as a pentamer by plasma cells; It is the first antibody secreted into the blood during the early stages of a primary response.
IgE (regain) Has a special affinity for receptors on the plasma membranes of basophils in the blood or mast cells in the tissues; humans can develop allergies, such as drugs, pollens, and certain foods.
IgD Is found mainly on B-cells membranes and is rarely secreted; It may help initiate immune responses and some allergic reactions; These levels rise in some autoimmune conditions.
Primary response This antibody occurs when the antigen is first recognized by host B cells.
Secondary response When an antigen recognized by memory cells enters the blood.
Compromised host An individual w/ reduced resistance.
Factors that modify immune responses: Age; seasonal patterns; environmental factors such as pollution and exposure to radiation, to include tobacco smoke.
Created by: jenilee80