Duodenum

The duodenum is the first part of the small intestine. It receives partially digested food from the stomach, along with digestive juices from the pancreas and gallbladder. These juices contain enzymes that help break down carbohydrates, fats, and proteins.

Jejunum

The jejunum is the middle section of the small intestine and is where the majority of nutrient absorption takes place. The walls of the jejunum are lined with tiny finger-like projections called villi, which increase the surface area for absorption. Nutrients from the digested food pass through the walls of the jejunum and into the bloodstream to be transported to the body's cells.

Ileum

The ileum is the final part of the small intestine and is primarily responsible for the absorption of vitamin B12 and bile salts. It also helps to complete the absorption of any remaining nutrients before the indigestible residue moves into the large intestine.

Study Guide

To understand the small intestine better, consider the following study guide:

Anatomy of the Small Intestine

- Identify and label the three parts of the small intestine: duodenum, jejunum, and ileum. - Describe the structure and function of the villi in the small intestine.

Role in Digestion and Absorption

- Explain the role of the small intestine in the digestion of carbohydrates, fats, and proteins. - Discuss the process of nutrient absorption in the small intestine, including the transport of nutrients into the bloodstream.

Comparison with Other Digestive Organs

- Compare and contrast the functions of the small intestine with those of the stomach and large intestine. - Explain how the small intestine works in conjunction with the pancreas and gallbladder for digestion.