PhysiologyLesson 5 of 7 in the course The Digestive System

Small- and Large-Intestine Structure, Digestion, and Motility

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

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Summary

This lesson introduces the small intestine, the longest part of the alimentary canal and the body's primary site of digestion and absorption. Its regions and connections prepare us to understand how food moves through the digestive system.

The small intestine receives chyme from the stomach. Most digestion occurs here, and practically all nutrient absorption takes place here. In a living person, it is about 3.05 m (10 ft) long, though it may measure about twice that length in a cadaver because muscle tone is lost after death.

All flashcards

Why is the small intestine called “small” despite its length?
The name refers to its relatively small diameter, about 2.54 cm (1 in), compared with the large intestine's diameter of about 7.62 cm (3 in).
What are the three regions of the small intestine in order?
The duodenum, jejunum, and ileum, moving from the stomach toward the large intestine.
What happens at the hepatopancreatic ampulla?
The bile duct and main pancreatic duct join there. Their secretions enter the duodenum through the major duodenal papilla, with flow regulated by the hepatopancreatic sphincter.
How does the ileum connect to the large intestine?
The ileum joins the cecum, the first part of the large intestine, at the ileocecal sphincter or valve.
What is the route of nutrient-rich blood from the small intestine to the liver?
Blood drains toward the superior mesenteric vein and is then carried to the liver through the hepatic portal vein.

Quiz questions

  1. What is the primary reason the small intestine is called “small”?Answer: Its diameter is smaller than that of the large intestine.
  2. Which sequence lists the regions of the small intestine from proximal to distal?Answer: Duodenum, jejunum, ileum
  3. Where do the bile duct and main pancreatic duct join?Answer: At the hepatopancreatic ampulla
  4. Which structure regulates the flow of bile and pancreatic juice into the duodenum?Answer: The hepatopancreatic sphincter
  5. Which venous route carries nutrient-rich blood from the small intestine toward the liver?Answer: Superior mesenteric vein to hepatic portal vein

Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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