ch. 22 micro – Flashcards
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Defenses of the GI tract against pathogens include
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A. mucus, acid, and saliva. B. secretory IgA and lysozyme. C. peristalsis. D. GALT. E. All of the choices are correct.**correct answer
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The streptococci attach to the surface of the teeth with:
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O antigens
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Which organ of the GI tract has a large, commensal population of microorganisms?
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large intestine
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The most common infectious disease in humans is
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dental caries.
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The main causes of dental caries seem to be
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Both Streptococcus mutans and Streptococcus sobrinus are correct.
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Oral bacteria on the tooth surface
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A. develop a biofilm. B. use bacterial cell structures such as fimbriae and slime layers to adhere. C. include streptococci that metabolize sucrose, produce sticky glucans, and form plaque. D. All of the above.**correct answer
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Gingivitis
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A. is primarily caused by normal anaerobic biota. B. involves the formation of calculus and plaque. C. involves a crevice in the gum along the tooth. D. may involve archaeal species. E. All of the choices are correct.**correct answer
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All of the following are true of acute necrotizing ulcerative gingivitis (ANUG) except it
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is very communicable.
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The causative organism for mumps is
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Paramyxovirus
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The virulence factor for mumps is
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spike-induced syncytium.
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Orchitis and epididymitis are seen in young, adult males as a complication of
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mumps.
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Helicobacter pylori causes
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A. gastritis. B. duodenal ulcers. C. stomach ulcers. D. increased risk for stomach cancer. E. All of the choices are correct.**correct answer
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Which is not a characteristic of Helicobacter pylori?
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produces enteroxin that causes diarrhea
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Which of the following antigen types found in gram-negative enterics is mismatched?
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All of the choices are correct.
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Salmonella are
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motile.
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Typhoid fever has all of the following characteristics except
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spread by droplet contact.
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Salmonelloses are
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A. not caused by Salmonella typhi. B. associated with undercooked poultry and eggs, and reptile and rodent feces. C. gastroenteritis with vomiting and diarrhea. D. treated with fluid and electrolyte replacement. E. All of the choices are correct.**correct answer
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Which statement does not accurately describe Salmonella typhi?
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It produces a mild gastrointestinal disease.
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Which is incorrect about shigellosis?
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It frequently involve septicemia.
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Shigella species have all of the following characteristics except
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they produce urease and hydrogen sulfide.
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E. coli O157:H7 characteristics include all of the following except it
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only causes occupational illness in people who work with animals.
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Which of the following is not a virulence factor of E. coli O157:H7?
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secretes shiga exotoxin from the E. coli chromosome
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Which of the following is not true of enterotoxigenic E. coli (ETEC)?
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causes a high fever
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Which of the following is not true of enterovasive E. coli (EIEC)?
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produces shiga toxin
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Escherichia coli infections
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A. All of the choices are correct.**correct answer B. are often transmitted by fecal contaminated water and food. C. involve enterotoxin in traveler's diarrhea. D. include EIEC that destroys gut mucosa. E. are self-limiting with the only treatment being rehydration.
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All of the following are characteristics of Campylobacter jejuni except
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infects the stomach.
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The most common bacterial cause of diarrhea in the United States is
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Campylobacter.
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Campylobacter infection has all of the following characteristics except
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is caused by a shiga toxin.
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Which is true of Yersinia enterocolitica and Yersinia pseudotuberculosis?
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They cause intense pain caused by inflammation of the ileum and mesenteric lymph nodes.
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Production of enterotoxin is a characteristic of
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Clostridium difficile.
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All of the following pertain to Clostridium difficile infection except it
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is due to ingestion of contaminated, improperly stored, cooked meats and gravies
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Which is not true of Clostridium difficile?
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produces "rice-water" stools
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The virulence of Vibrio cholerae is due to its
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enterotoxin.
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Cholera symptoms are
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A. copious watery diarrhea. B. loss of blood volume. C. acidosis, sunken eyes, and thirst. D. hypotension, tachycardia, and shock. E. All of the choices are correct.**correct answer
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The most immediate and important treatment needed to prevent death in cholera victims is
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water and electrolyte replacement.
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"Rice-water stools" are associated with disease caused by which organism?
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Vibrio cholerae
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Outbreaks of which apicomplexan disease have been associated with fecal-contaminated drinking water?
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cryptosporidiosis
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Symptoms of cryptosporidiosis include
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headache, sweats, vomiting, severe abdominal cramps, and diarrhea.
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The primary viral cause of chronic diarrhea globally is
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rotavirus.
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Which of the following is not a normal causative agent of acute diarrhea with vomiting (food poisoning)?
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Clostridium difficile
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A common food intoxication is caused by enterotoxin-producing strains of
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Staphylococcus aureus.
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Which is incorrect about Staphylococcus aureus food intoxication?
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Ingestion of the pathogen allows it to multiply and damage the GI tract lining.
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Outbreaks of which apicomplexan disease have been associated with fecal-contaminated imported raspberries, fresh greens, and drinking water?
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cyclosporiasis
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Entamoeba histolytica is acquired by
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A. ingestion of cysts of the pathogen. B. contaminated food. C. contaminated water. D. anal-oral sexual contact. E. All of the choices are correct.**correct answer
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All of the following can be transmitted by drinking contaminated water except
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malaria
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Giardiasis involves
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symptoms of abdominal pain, flatulence, and diarrhea.
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Inflammation of the liver with necrosis of the hepatocytes and swelling due to a mononuclear response is a disease called
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hepatitis.
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Hepatitis B virus
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A. is principally transmitted by blood. B. transmission risks include shared needles, anal intercourse, and heterosexual intercourse. C. is transmitted to the newborns from chronic carrier mothers. D. has many chronic carriers. E. All of the choices are correct.**correct answer
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Hepatitis B infection
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increases risk for hepatocellular cancer.
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Which is incorrect about hepatitis A infection?
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predisposes a person for liver cancer.
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Which is mismatched?
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hepatitis D virus - defective RNA virus that coinfects with HAV
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The most common cause of liver cancer in the United States is
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HCV.
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Parasitic helminths exhibit all of the following characteristics except
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have larval forms that do not affect humans.
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Ascaris lumbricoides
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A. is an intestinal roundworm. B. spreads to humans by ingestion of Ascaris eggs in food. C. larvae penetrate into lymphatics and capillaries around intestines. D. larvae migrate to the pharynx, get swallowed, and return to intestines to mature. E. All of the choices are correct.**correct answer
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Enterobius vermicularis is
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an intestinal helminth that easily contaminates fingers and fomites.
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All of the following pertain to tapeworms except
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they can produce a variety of toxins.
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General symptoms of helminth infection includes all of the following except
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intense abdominal pain.
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Characteristics of trichinosis include
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A. encysted larvae getting ingested. B. association with undercooked pork or bear meat. C. migration from intestines to blood and various body tissues. D. coiled larvae encyst in skeletal muscle E. All of the choices are correct.**correct answer
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Liver flukes live in all of the following areas except the
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small intestine.
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Which of the following is not true of schistosomiasis?
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These helminths can invade the brain.
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Which of the following infections involves intermediate development in snails and freshwater fish?
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Both Clonorchis sinensis and Opisthorchis sinensis are correct.
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Which of the following helminths is paired with a correct characteristic of its pathogenesis?
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Taenia solium - eggs or larvae can be ingested
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In the absence of dietary carbohydrates, bacteria do not cause tooth decay.
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true
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Mumps causes permanent sterility in young male adults.
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false
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E. coli O157:H7 secretes shiga exotoxin.
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true
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Antibiotics are used to treat E. coli O157:H7-caused diarrhea.
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false
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Enteropathogenic E. coli (EPEC) causes gut effacement with shiga toxin.
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false
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The best treatment for acute diarrhea is oral replacement of electrolytes and water.
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true
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Only feces from humans that contaminates food and water can be involved in transmission of amoebiasis.
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false
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Boiling will not inactivate Giardia lamblia cysts in contaminated water.
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false
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Carriers of Hepatitis B virus are not common
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false
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There are vaccines for immunity to the Hepatitis B virus.
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true
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The only body fluid that can transmit Hepatitis B virus is blood.
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false
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Most antihelminthic medications act only against the pathogens, not the human host.
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false
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There are no infectious agents that can invade intact skin.
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false
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Research does not indicate a link between the numbers and types of bacteria causing periodontitis and thicker carotid arteries in an individual.
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false
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Despite acidic conditions, some microorganisms have been found residing within the human stomach.
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true
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Most of the bacteria involved in periodontal disease are obligate (strict) anaerobes. Predict why this is the case.
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The crevice area between the gingiva and the tooth is low in oxygen.
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Of the helminths named below, one of them does not belong with the others. Which statement correctly explains the reason? Enterobius (pinworm)....Fasciola (fluke).....Necator (hookworm)......Diphyllobothrium (tapeworm)
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One of the helminths is associated with the liver, whereas the others are in the intestines.
