Ileum

Definition

The ileum is the final and longest segment of the small intestine, following the duodenum and jejunum. It is primarily responsible for the absorption of nutrients and bile acids.

5 Must Know Facts For Your Next Test

1. The ileum measures approximately 2-4 meters in length in adults.
2. It contains specialized cells called Peyer's patches that play a role in immune function.
3. Vitamin B12 and bile salts are specifically absorbed in the ileum.
4. The ileum connects to the large intestine at the ileocecal valve.
5. Peristalsis aids the movement of digested food through the ileum toward the large intestine.

Review Questions

• What specific nutrients are absorbed in the ileum?
• Where does the ileum connect to the large intestine?
• What role do Peyer's patches play in the ileum?

Related terms

duodenum:

The first segment of the small intestine where most chemical digestion occurs.

jejunum:

The middle section of the small intestine, primarily involved in nutrient absorption.

ileocecal valve: A sphincter muscle that regulates passage from the ileum to the cecum of the large intestine.