Small Intestine - Video Tutorials & Practice Problems
Functions of the Small Intestine
Regions of the Small Intestine
Small Intestine Example 1
Which pathway correctly identifies the path of chyme as it moves through the small intestine?
Jejunum → Duodenum → Cecum.
Duodenum → Ileum → Cecum.
Ileum → Jejunum → Duodenum.
Duodenum → Jejunum → Ileum.
Where are bile salts reabsorbed in the small intestine?
Duodenum.
Jejunum.
Ileum.
Cecum.
As a treatment for certain diagnoses, a section of the small intestine may be removed from a patient. Based on your understanding of their respective functions, a portion of which section of intestine do you think could be removed with the fewest adverse side effects and why?
The Ileum, very little chemical digestion or nutrient absorption occurs in the Ileum.
The Ileum, the primary role of the ileum is to secrete digestive enzyme which can be supplemented.
The jejunum, digestive enzymes secreted by the jejunum can be supplemented and most absorption takes place in the ileum.
The jejunum, the primary role of the jejunum is to mix chyme and enzymes, which can occur in other regions.
Microscopic Anatomy
Small Intestine Example 2
A lacteal can be found within each:
Intestinal fold.
Brush border.
Microvillus.
Villus.
The brush border enzymes are associated with which level of the small intestine?
Circular folds.
Intestinal crypts.
Microvillus.
Villus.
Which of the following statements is true?
The microvilli contain capillary beds so that nutrients can be absorbed efficiently.
The villi are largest in the duodenum and decrease in size throughout the length of the small intestine.
Lacteals are found in the intestinal crypts and are the location of fat absorption.
The circular folds of the small intestine are found in the jejunum and the ileum but not in the duodenum.
Cell Types of the Intestinal Mucosa
Small Intestine Example 3
The most numerous type of epithelial cells in the small intestine are the
Paneth cells.
Enterocytes.
Goblet cells.
Enteroendocrine cells.
Both Paneth cells and Peyer’s patches are more numerous in the ileum than in the jejunum or the duodenum. Which statement below correctly describes why that may be?
The ileum is adjacent to the large intestine where there are high levels of intestinal microbes.
The ileum is responsible for absorbing any remaining nutrients not absorbed by the jejunum.
The ileum has the highest pH of any region of the small intestine.
The intestinal folds and villi are relatively smaller in the ileum than in the duodenum and jejunum.
Motility in the Small Intestine
Which of the following statements are true about motility in the small intestine:
I. Peristalsis will generally propel chyme towards the ileocecal valve.
II. The efficiency of chemical digestion can be increased through segmentation.
III. Peristalsis and segmentation use the same muscles, but contract in different patterns.
I only.
II only.
I & II.
I & III.
II & III.
Putting it Together: Overview of Small Intestinal Function
Small Intestine Example 4
Celiac disease is a condition where the body has an abnormal immune response to the protein gluten found in wheat and other grains. A result of this, the body’s immune response can cause damage to the villi. Based on your knowledge of the small intestine, what function would this this most directly affect?
Immune function in the ileum.
Chemical digestion in the duodenum.
Absorption in the jejunum.
Motility in all three regions of the small intestine.
Gastric bypass surgery involves creating an alternate pathway for food that bypasses the majority of the stomach and a portion of the small intestine to help patients lose weight. A schematic is shown below.
Why do you think it is important to attach the duodenum to the jejunum even if food is no longer passing through it?
The gastric juice produced in the bypassed portion of the stomach is needed for digestion in the small intestine.
The duodenum produces brush border enzymes needed for chemical digestion.
Peristalsis in the duodenum will propel chyme through the GI tract.
The duodenum receives bile and pancreatic juices needed for chemical digestion.
Two chyme samples are taken: one from the stomach and one from the duodenum. How could you tell the samples apart using lab techniques?
Test for the presence brush border enzymes; the duodenal chyme will contain brush border enzymes while the stomach chyme will not.
Test for the presence of bile salts; the stomach chyme will contain bile salts, but the duodenal chyme will not.
Test the pH of each solution; the stomach chyme will be more acidic than the duodenal chyme.
Test for the presence of starch; starches are digested in the stomach, so only simple sugars are present in the small intestine.
Lactose, a sugar found in milk, can only be digested by lactase, a brush border enzyme. All babies produce lactase, but only some adults do. Adults who do not produce lactase are referred to as lactose intolerant, as the presence of undigestible lactose can lead to uncomfortable digestive side effects such as gas and diarrhea. Based on your understanding of the small intestine, where would you expect to find the most lactase in babies and those adults that can digest lactose?
Duodenum.
Jejunum.
Ileum.
Cecum.
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