Ileum

Definition

The ileum is the final section of the small intestine, connecting the jejunum to the cecum of the large intestine. It plays a crucial role in the absorption of nutrients, such as vitamins, minerals, and bile salts, as well as the continuation of digestion. The ileum's structure includes numerous villi and microvilli, which increase its surface area for optimal nutrient absorption, making it vital for overall digestive health.

5 Must Know Facts For Your Next Test

1. The ileum is approximately 3-4 meters long in adults and makes up about 60% of the small intestine's length.
2. It is responsible for absorbing essential nutrients like vitamin B12 and bile acids, which are critical for digestion and metabolism.
3. The ileum contains Peyer's patches, which are lymphoid tissues that play an important role in immune function by monitoring intestinal bacteria.
4. Unlike other parts of the small intestine, the ileum has fewer villi and a thinner wall, adapting its structure for specific absorption needs.
5. Disorders affecting the ileum, such as Crohn's disease or ileitis, can lead to malabsorption issues and significant health challenges.

Review Questions

• How does the structure of the ileum facilitate nutrient absorption compared to other parts of the small intestine?
  • The structure of the ileum features a high density of villi and microvilli, which maximize its surface area for nutrient absorption. Compared to the duodenum and jejunum, while they also have villi, the ileum is specialized for absorbing specific nutrients like vitamin B12 and bile acids. This unique adaptation ensures that the body efficiently extracts remaining nutrients before waste moves into the large intestine.
• Discuss the role of Peyer's patches in the ileum and their significance in maintaining intestinal health.
  • Peyer's patches are clusters of lymphoid tissue located in the wall of the ileum that play a crucial role in monitoring intestinal bacteria and defending against pathogens. By producing immune responses when needed, they help maintain a healthy balance of gut microbiota. This surveillance system is essential for preventing infections and ensuring that beneficial bacteria thrive while harmful ones are kept in check.
• Evaluate how diseases affecting the ileum can impact overall digestive health and nutrient absorption.
  • Diseases such as Crohn's disease or ileitis can severely disrupt normal functioning of the ileum, leading to inflammation and scarring that hinders nutrient absorption. This can result in deficiencies in essential vitamins and minerals like vitamin B12 and iron. Over time, malabsorption can cause significant health problems such as anemia, weight loss, and compromised immune function, highlighting the importance of a healthy ileum in overall digestive health.

Related terms

Jejunum:

The jejunum is the middle section of the small intestine, situated between the duodenum and the ileum, where most nutrient absorption occurs.

Villi:

Tiny, finger-like projections that line the walls of the small intestine, including the ileum, increasing the surface area for enhanced absorption of nutrients.

Cecum:

The first part of the large intestine, where the ileum connects and where undigested food begins its transition into the colon.