Deck 20: Diseases of the Gastrointestinal System

Question 1

Which choice best describes the antimicrobial activities in the mouth?

A) IgA secreted into the mucus coating prevents pathogen binding
B) production of enzymes that degrade bacterial peptidoglycan.
C) hydrochloric acid denatures proteins and killing many microbes
D) presence of activated macrophages that ingest pathogens

Answer 1

B

Question 2

Microbiota of the stomach include which of the following organisms?

A) Streptococcus salivarius
B) Streptococcus mutans
C) Bacterioides spp.
D) Lactobacillus spp.

Answer 2

D

Question 3

What is the greatest barrier that pathogens must overcome in order to cause disease in the GI Tract?

A) finding attachment locations
B) surviving high acidity of the stomach
C) avoiding the inflammatory response in the intestinal tract
D) being expelled with the feces

Answer 3

B

Question 4

Which factor(s) contribute(s) to the Infectious Dose (ID₅₀) of GI pathogens? (Select all that apply)

A) variations in sensitivity to stomach acid
B) number of pathogens ingested
C) type of pathogen ingested
D) type of food consumed

Question 5

Of the four pathogens listed, which is the most able (pathogenic) to cause GI disease?

A) Salmonella spp.: ID₅₀ = 1.8 X 10⁵
B) Cryptosporidium parvum: ID₅₀ = 173
C) Rotavirus: ID₅₀ = 6.1
D) Campylobacter jejuni: ID₅₀ = 8.9 X 10²

Question 6

As humans age, the makeup of the resident microbiota in the mouth changes. Which of the following descriptions is an INCORRECT match?

A) newborn babies/ oral cavity is sterile
B) nursing babies/microbiota like Streptococcus mutans from mother transferred to infant
C) teething babies/S. mutans and S. sanguis take up residence because they adhere to tooth surface
D) adolescents/Bacteroides and spirochetes colonize oral cavity

Question 7

Where are most of the resident microbiota of the GI tract found?

A) oral cavity
B) upper portion of small intestine
C) lower portion of small intestine
D) large intestine

Question 8

Select the statement that best describes microbiota present in the large intestine.

A) contains the lowest concentration of bacteria in the human body
B) the main species are aerobic, gram-negative bacteria
C) E. coli is the predominant fecal coliform
D) sulfur producing bacteria are found in high concentrations

Question 9

Dental caries may be prevented by which of the following activities?

A) regular brushing and flossing
B) drinking fluoride-containing water
C) removal of dental plaque during regular hygiene visits
D) all of the above

Question 10

The process that leads to tooth decay includes which if the following?

A) Streptococci and other bacteria ferment sugars with resulting acid by-products
B) acid by-products slowly dissolve hard enamel
C) destruction of enamel allows means for bacteria to penetrate into living pulp
D) all are correct

Question 11

Which strategy is not appropriate for the treatment of dental caries?

A) chewing on cloves and taking pain killers will eventually resolve the problem
B) prevention of decay spreading into pulp area
C) systemic broad-spectrum antibiotic treatment to target any pulp infection if needed
D) removal of damaged enamel and permanent filling of damaged area

Question 12

Why does the addition of fluoride to municipal water supplies greatly reduce tooth decay in the population?

A) fluoride speeds tooth demineralization by degrading the enamel
B) tooth veneer with fluoride is more resistant than the natural hydroxyapatite of the enamel
C) fluoride serves as a good antiseptic in reducing the number of acid-producing bacteria in the oral cavity
D) fluoride acts like chlorine and kills bacteria in the water supply

Question 13

Which characteristic is not associated with gingivitis?

A) swollen tissues
B) red and painful tissues
C) loosening and loss of teeth
D) accumulation of bacterial plaque in gingival crevices

Question 14

Risk of gingivitis may be reduced by use of mouthwashes containing which ingredient?

A) chlorhexidine
B) triclosan
C) iodine
D) phenol

Question 15

Which statement best describes periodontitis?

A) an inflammatory disease of tooth-supporting structures
B) it is caused by plaque buildup on the teeth
C) it is caused by poor oral hygiene
D) all are correct

Question 16

Periodontitis is a less serious oral disease than gingivitis.

Question 17

Periodontal Disease increases the risk of suffering heart disease and stroke by approximately 20%.

Question 18

Which statement accurately describes gingipan antigens?

A) they stimulate increased production of amyloid beta in humans
B) they have been detected in the brains of Alzheimer's patients
C) they are amylases produced by Porphyromonas gingivalis
D) all of the above

Question 19

How does Helicobacter pylori survive in the acidic environment of the stomach?

A) it is an acidophile
B) it produces the enzyme catalase
C) it breaks down urea to release ammonia that neutralizes stomach acid
D) all are correct

Question 20

How do clinicians diagnose peptic ulcer disease caused by Helicobacter pylori?

A) detection of hydrogen peroxide when urea is broken down
B) measurement of carbon dioxide level one hour after ingestion of a urea pill
C) use of rapid ELISA test to detect H. pylori antigens in blood
D) all of the above may be used to diagnose disease

Question 21

What is an appropriate treatment for peptic ulcer disease?

A) use of proton pump inhibitor
B) use of amoxicillin
C) use of clarithromycin
D) use of fluoride treatments

Question 22

Staphylococcus aureus causes a severe GI disease because the microbe penetrates GI mucosa.

Question 23

Why is Staphylococcus aureus so often implicated in food poisoning?

A) it grows in environments with low osmotic pressure
B) it grows best in foods with either low salt or low sugar content
C) the enterotoxin it produces is heat stable
D) Staphylococcus enterotoxin is easily degraded by proteases of digestive system

Question 24

Which statement best describes the clinical features of staphylococcal food poisoning?

A) signs and symptoms include nausea, vomiting, abdominal cramps and prostration
B) vomiting begins approximately 18-24 hr. after contaminated food ingestion
C) severity of disease depends upon how many bacteria were ingested
D) although vomiting, patients feel fine and continue to go about daily activities

Question 25

What practices help prevent Staphylococcus aureus food intoxication?

A) proper hygiene habits by food handlers, the main source of contamination
B) reheating of cooled foods
C) regular disinfection of equipment and food surfaces
D) maintenance of proper refrigerator and stove temperatures

Question 26

What is the best and most effective treatment for diarrheal disease?

A) antibiotic therapy
B) oral rehydration therapy
C) antidiarrheal medication
D) all are correct

Question 27

Which statement characterizes uncomplicated lower GI disease?

A) the etiological agent typically is not identified
B) disease may be complicated by fever, bloody stools, vomiting and abdominal pain
C) disease usually resolves within several days with no further problems
D) all are correct

Question 28

Your patient reports 3 days of bloody diarrhea and fever. You isolate a gram-negative, lactose fermenting bacillus. The likely cause of this lower GI disease is which of the following?

A) Listeria monocytogenes
B) Clostridioides difficile
C) Vibrio cholera
D) E. coli

Question 29

Your patient reports loose stools and abdominal cramping after consuming a smoothie prepared with raw eggs. You isolate a gram-negative, H₂S producing (on HE agar) bacillus. Identify the likely pathogen.

A) Listeria monocytogenes
B) Salmonella spp.
C) Vibrio cholera
D) E. coli

Question 30

Your 80 year old patient reports diarrhea, fever, and smelly stools. She recently completed a course of antibiotic therapy for a UTI. The lab isolates an endospore forming, gram-positive, anaerobe. Identify the likely pathogen.

A) Listeria monocytogenes
B) Clostridioides difficile
C) Vibrio cholera
D) E. coli

Question 31

Your patient reports watery stools after consuming a smoothie prepared with raw milk. The laboratory attempts culture of a fecal specimen under 5% CO₂ and reports growth of a gram-negative, spiral-shaped, flagellated organism. What is the likely pathogen in this case?

A) Listeria monocytogenes
B) Shigella spp.
C) Salmonella typhi
D) Campylobacter jejuni

Question 32

Which statement(s) appropriately describe(s) typhoid fever?

A) the disease is caused by a species of Salmonella found in food and water with fecal contamination
B) the disease is rare where there are good sanitation systems
C) a rose-spot rash is often present
D) Salmonella enteritidis is the etiological agent

Question 33

The most pathogenic strain of E. coli is O157:H7 and it is acquired via consumption of undercooked beef

Question 34

HUS is most often effectively treated with antibacterial drugs.

Question 35

Which of the following diseases may present with bloody diarrhea?

A) Salmonellosis
B) Shigellosis
C) Campylobacteriosis
D) Hemorrhagic colitis

Question 36

Which statement accurately describes the action of V. cholera exotoxin?

A) the toxin influences cellular release of cAMP causing ions and H₂O to be pumped into the intestinal lumen.
B) the toxin causes absorption of fluid into intestinal cells and secretion of chloride ions
C) the toxin causes hydrolysis of cellular ATP and consequent release of calcium ions into the intestinal lumen
D) all of the above are correct

Question 37

What virus causes latent infection in the facial nerve ganglia?

A) Herpes simplex type I
B) Hepatitis E virus
C) Rotavirus
D) None of the above

Question 38

Which ss RNA virus causes parotitis?

A) HSV II
B) Norovirus
C) Mumps virus
D) None of the above

Question 39

Which characteristics appropriately describe Norovirus disease?

A) it is caused by a DS RNA virus
B) the ID₅₀ value is very low
C) it can be prevented with vaccination
D) It is a diarrheal disease lasting 1-2 days

Question 40

Which demographic group is most often infected by rotavirus?

A) breast fed newborns
B) adults: ages 65 and older
C) infants: 4-24 months of age
D) adolescents: ages 2-12 years

Question 41

Hepatitis A disease is caused by a DS RNA virus that is transmitted via contaminated blood products.

Question 42

What pathologies cause jaundice to develop in Hepatitis A infection?

A) inflammation of the liver
B) decreased ability to metabolize bilirubin
C) viral replication in liver cells
D) none of the above

Question 43

Which of the following protozoans causes bloody diarrhea?

A) Giardia lamblia
B) Entamoeba histolytica
C) Crytosporidium parvum
D) protozoans do not cause bloody diarrhea

Question 44

Metronidazole is the treatment of choice for which protozoan diseases of the GI system?

A) Giardiasis and Amoebiasis
B) Giardiasis and Cryptosporidiosis
C) Amoebiasis and Cryptosporidiosis
D) Giardiasis, Amoebiasis and Cryptosporidiosis

Question 45

Your patient presents with diarrhea, bloating, and cramping. They report drinking untreated river water on a camping trip. You lab notes oval cysts upon O & P examination. Flagellated protists are also observed.

A) Giardia lamblia
B) Entamoeba histolytica
C) Crytosporidium parvum
D) Ascariasis lumbrecoides

Question 46

Pinworms eggs are deposited into and transferred in feces.

Question 47

Your patient presents with loose stools and abdominal cramps. They report eating a raw beef dish several weeks ago. O & P examination reveals proglottids in the feces. What is the probable infectious agent?

A) Schistosoma mansoni
B) Ancylostoma duodenale
C) Enterobius vermicularis
D) Taenia saginata

Question 48

Which Nematode infection results from consumption of eggs contaminating the soil with resulting malnutrition, especially in children?

A) schistosomiasis
B) hookworm infection
C) ascariasis
D) dwarf tapeworm infection

Question 49

Hookworms have a complex life cycle that includes which one of the following activities?

A) host ingestion of eggs
B) humans as an intermediate host
C) larval penetration of human skin through hair follicles or small abrasions
D) release of proglottids in feces

Question 50

Which of the listed activities is most likely to prevent hookworm infection?

A) vaccination against hookworms
B) administration of albendazole
C) cooking food appropriately and practicing good hand hygiene
D) shoe wearing