Question 1

Which of the following is NOT considered a natural defense of the gastrointestinal tract?

Accepted Answer

Ciliated epithelia

Question 2

A patient presents with severe, watery diarrhea after a course of broad-spectrum antibiotics. Colonoscopy reveals yellowish plaques on the colon mucosa. Which organism is most likely responsible?

Accepted Answer

Clostridioides difficile

Question 3

Which of the following statements about the normal biota of the gastrointestinal tract is FALSE?

Accepted Answer

Accessory organs such as the liver and pancreas are normally colonized by bacteria.

Question 4

Which of the following is the primary virulence factor of Vibrio cholerae responsible for the profuse watery diarrhea seen in cholera?

Accepted Answer

Cholera toxin (CT)

Question 5

A 7-year-old child presents with pronounced anal itching, especially at night. Which helminth is most likely responsible, and what is the best diagnostic test?

Accepted Answer

Enterobius vermicularis; adhesive tape test

Question 6

Which of the following organisms is most commonly associated with food poisoning due to heat-stable enterotoxin in unrefrigerated custards and cream pastries?

Accepted Answer

Staphylococcus aureus

Question 7

Which of the following is a distinguishing feature of Shigella pathogenesis compared to Salmonella?

Accepted Answer

Shigella invades the villus cells of the large intestine but does not invade the bloodstream.

Question 8

A patient develops acute, bloody diarrhea after eating undercooked ground beef. Laboratory testing reveals Shiga toxin in the stool. Which organism is most likely responsible?

Accepted Answer

Shiga-toxin-producing Escherichia coli (STEC)

Question 9

Which of the following best describes the mechanism by which Helicobacter pylori survives in the acidic environment of the stomach?

Accepted Answer

It produces urease, which breaks down urea to form ammonia and neutralize acid.

Question 10

Which of the following hepatitis viruses is most likely to cause chronic infection and liver cancer in the United States?

Accepted Answer

Hepatitis C virus

Question 11

A patient presents with fever, malaise, and swelling of the parotid glands. Which disease is most likely, and what is the best prevention strategy?

Accepted Answer

Mumps; MMR vaccination

Question 12

Which of the following is a hallmark laboratory finding in helminthic infections?

Accepted Answer

Eosinophilia

Question 13

Which of the following is the most effective way to prevent dental caries?

Accepted Answer

Dietary restriction of sucrose and refined carbohydrates

Question 14

A patient develops watery diarrhea after swimming in a public pool. The organism is resistant to chlorine and can be detected by acid-fast staining. What is the most likely causative agent?

Accepted Answer

Cryptosporidium

Question 15

Which of the following best explains why antibiotics are contraindicated in most cases of STEC infection?

Accepted Answer

Antibiotics may increase pathology by releasing more Shiga toxin.

Question 16

Which of the following helminths is associated with the development of neurocysticercosis when humans ingest its eggs?

Accepted Answer

Taenia solium

Question 17

A patient presents with dysentery, abdominal pain, and flask-shaped ulcers in the colon. Which protozoan is most likely responsible?

Accepted Answer

Entamoeba histolytica

Question 18

Which of the following is a common feature of all helminths that infect the gastrointestinal tract?

Accepted Answer

They have specialized mouthparts for attaching to tissues and feeding.

Question 19

Which of the following best describes the transmission cycle of Diphyllobothrium latum?

Accepted Answer

Life cycle C: humans acquire infection by eating raw or undercooked fish containing larvae.

Question 20

Which of the following is the most common cause of foodborne illness in the United States?

Accepted Answer

Norovirus

Infectious Diseases Affecting the Gastrointestinal Tract: Anatomy & Physiology Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards