PathologyLesson 1 of 5 in the course Digestive System Infections

Digestive Anatomy, Microbiota, GI Defenses, and Disease

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

The digestive system begins in the mouth, where food is mechanically and chemically processed. This lesson introduces the route food takes through the digestive tract and focuses on oral anatomy, tooth structure, and the mouth’s normal microbiota.

The gastrointestinal (GI) tract is a continuous passage extending from the mouth to the anus. Food travels through the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus. The mouth includes the teeth, gums, tongue, oral vestibule (the space between the lips, cheeks, teeth, and gums), and oral cavity proper (the space behind the teeth and gums).

All flashcards

Which structures increase the small intestine’s absorptive surface area?
Folds called villi and the microvilli on enterocytes increase the absorptive surface area.
Which vitamins can bifidobacteria synthesize?
Bifidobacteria can synthesize vitamin B12, folate, and riboflavin.
What pH range typically characterizes the stomach?
The stomach’s acidic environment typically has a pH of 1.5–3.5.
How does mucus help defend the gastrointestinal tract?
Mucus forms a protective layer that reduces pathogen access to deeper tissues.
How does digestive infection differ from intoxication?
Infection involves a pathogen entering and growing in the body; intoxication results from exposure to a toxin.

Quiz questions

  1. What is the primary digestive role of bile in the small intestine?Answer: It emulsifies fats.
  2. What is competitive exclusion in the gastrointestinal tract?Answer: Resident microbes compete with potential pathogens for space and nutrients.
  3. What do intestinal microfold (M) cells do?Answer: They transfer antigens from the intestinal lumen to immune cells.
  4. What is a defining feature of dysentery as described in gastrointestinal disease?Answer: Watery stools containing blood and excess mucus.
  5. How can oral microbial activity contribute to tooth decay?Answer: Microbial fermentation produces acids that can damage teeth.

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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