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BIO 140 Human Biology I - Questions and Solutions

Digestive System Processes and Regulation - Solutions

Review Questions

1. Which of these processes occurs in the mouth?

  1. ingestion
  2. mechanical digestion
  3. chemical digestion
  4. all of the above

2. Which of these processes occurs throughout most of the alimentary canal?

  1. ingestion
  2. propulsion
  3. segmentation
  4. absorption

3. Which of the following stimuli activates sensors in the walls of digestive organs?

  1. breakdown products of digestion
  2. distension
  3. pH of chyme
  4. all of the above

4. Which of these statements about reflexes in the GI tract is false?

  1. Short reflexes are provoked by nerves near the GI tract.
  2. Short reflexes are mediated by the enteric nervous system.
  3. Food that distends the stomach initiates long reflexes.
  4. Long reflexes can be provoked by stimuli originating outside the GI tract.

 

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Critical Thinking Questions

1. Offer a theory to explain why segmentation occurs and peristalsis slows in the small intestine. 

Solution: The majority of digestion and absorption occurs in the small intestine. By slowing the transit of chyme, segmentation and a reduced rate of peristalsis allow time for these processes to occur.

2. It has been several hours since you last ate. Walking past a bakery, you catch a whiff of freshly baked bread. What type of reflex is triggered, and what is the result?

Solution: The smell of food initiates long reflexes, which result in the secretion of digestive juices.

 

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OpenStax, Digestive System Processes and Regulation. OpenStax CNX. Jun 28, 2013 http://cnx.org/contents/afe83b13-0c1c-4d09-aa0b-4a0590580358@4. © June 28, 2013 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License 3.0 license.