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Ch. 25 - Microbial Diseases of the Digestive System
Tortora - Microbiology: An Introduction 14th Edition
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
All textbooksTortora 14th EditionCh. 25 - Microbial Diseases of the Digestive SystemProblem 4
Chapter 25, Problem 4

Gastric ulcers are caused by
a. Stomach acid.
b. H. pylori.
c. Spicy food.
d. Acidic food.
e. Stress.

Verified step by step guidance
1
Understand that gastric ulcers are lesions or sores that develop on the lining of the stomach.
Recognize that while stomach acid can contribute to ulcer formation, it is not the primary cause but rather a factor that exacerbates the condition.
Identify that Helicobacter pylori (H. pylori) is a type of bacteria that colonizes the stomach lining and is the main infectious agent responsible for causing most gastric ulcers.
Note that spicy food, acidic food, and stress may aggravate symptoms but are not direct causes of gastric ulcers.
Conclude that the correct cause of gastric ulcers among the options given is the bacterium H. pylori.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Helicobacter pylori and Gastric Ulcers

Helicobacter pylori is a type of bacteria that infects the stomach lining and is the primary cause of most gastric ulcers. It damages the protective mucous layer, allowing stomach acid to irritate the tissue, leading to ulcer formation.
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Role of Stomach Acid

Stomach acid (hydrochloric acid) aids digestion but can damage the stomach lining if protective mechanisms fail. While acid contributes to ulcer symptoms, it is not the root cause; rather, it exacerbates damage initiated by factors like H. pylori infection.
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Misconceptions about Ulcer Causes

Common beliefs such as spicy food, acidic food, and stress causing ulcers are largely myths. These factors may worsen symptoms but do not cause ulcers directly. Understanding this helps differentiate between causes and aggravating factors.
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Related Practice
Textbook Question

Microscopic examination of a patient’s fecal culture shows comma-shaped bacteria. These bacteria require 2-4% NaCl to grow. The bacteria probably belong to the genus

a. Campylobacter.

b. Escherichia.

c. Salmonella.

d. Shigella.

e. Vibrio.

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Textbook Question

Isolation of E. coli from a stool sample is diagnostic proof that the patient has

a. Cholera.

b. E. coli gastroenteritis.

c. Salmonellosis.

d. Typhoid fever.

e. None of the above

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Textbook Question

E. coli bacteria are part of the normal microbiota of the intestines and can cause gastroenteritis. Explain why this one species is both beneficial and harmful.

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Textbook Question

Complete the following table:

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Textbook Question

Identify the site colonized by the following organisms: E. granulosus, E. vermicularis, Giardia, H. pylori, hepatitis B virus, mumps virus, Rotavirus, Salmonella, Shigella, Streptococcus mutans, Trichinella spiralis, Trichuris.

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Textbook Question

Define mycotoxin. Give an example of a mycotoxin.

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