Small Intestine Anatomy and Function

Small Intestine Anatomy

• The duodenum is the first section of the small intestine, followed by the jejunum and then the ileum.
• The jejunum has the highest number of plicae circulares and a thicker wall, which is why it is the primary site for nutrient absorption.
• The ileum is the final section, measuring approximately 6 feet in length.
• The intestinal villi are composed of simple columnar epithelium, which increases the surface area for absorption.
• The superior mesenteric artery supplies blood to the midgut, encompassing most of the small intestines.

Small Intestine Function

• The duodenum is where the bile duct and pancreatic duct join to release their secretions.
• The hepatopancreatic ampulla, also known as the ampulla of Vater, is the structure that allows for the connection of these ducts into the duodenum.
• The Brunner's glands in the duodenum secrete mucus to protect the intestinal wall.
• The jejunum is responsible for the primary absorption of nutrients.
• The ileum is responsible for the absorption of water and vitamins.
• The mucosa layer of the small intestine contains villi, which further increase the surface area for nutrient absorption.

Explore the anatomy and functions of the small intestine, focusing on the three sections: duodenum, jejunum, and ileum. Understand their roles in nutrient absorption and the significance of various structures such as the hepatopancreatic ampulla and Brunner's glands.