Duodenum – Anatomy, Histology, Functions and FAQs

Introduction to Duodenum

Duodenum – Anatomy: The Duodenum is the first part of the small intestine. It is a short, coiled tube that is about 12 inches long. The Duodenum is located between the stomach and the jejunum, which is the second part of the small intestine. The Duodenum has three sections: the duodenal bulb, the duodenal body, and the duodenal cap. The duodenal bulb is the first part of the Duodenum. The duodenal body is the main part of the Duodenum. The duodenal cap is the last part of the Duodenum.

Anatomy of The Duodenum

• The duodenum is the first section of the small intestine. It is a C-shaped, coiled tube that is about 12 inches long. The duodenum is located between the stomach and the jejunum, the next section of the small intestine.
• The wall of the duodenum has three layers: the inner layer is made up of columnar epithelial cells; the middle layer is made up of connective tissue and smooth muscle; and the outer layer is made up of connective tissue and elastic tissue.
• The inner layer of the duodenum is where the digestive juices produced by the pancreas and the bile produced by the liver are secreted. The digestive juices and bile flow into the duodenum through small ducts that open into the duodenum wall.

The middle layer of the duodenum contains the following structures:

• The pancreas is a gland that sits just behind the stomach. The pancreas produces digestive juices that flow into the duodenum. The pancreatic juices contain digestive enzymes that break down food.
• The common bile duct is a duct that carries bile from the liver to the duodenum. Bile helps to digest fat.
• The ampulla of Vater is a structure that connects the pancreas and the common bile duct to the duodenum.

Histology of Duodenum

The duodenum is a part of the small intestine that is about 12 inches long. It is located between the stomach and the jejunum. The duodenum is responsible for the digestion of food.

The wall of the duodenum is made up of four layers:

• The mucosa is the innermost layer. It is made up of a thin layer of cells called epithelium. The epithelium is responsible for the secretion of digestive juices.
• The submucosa is a layer of connective tissue. It contains blood vessels, lymph vessels, and nerves.
• The muscularis is a layer of muscle. It contracts to move food through the duodenum.
• The serosa is the outermost layer. It is made up of a thin layer of cells called mesothelium. The mesothelium is responsible for the secretion of mucus.

Blood Supply and Innervation of Duodenum

• The duodenum is supplied with blood by the hepatic and pancreatic branches of the celiac trunk, and the superior and inferior mesenteric arteries. The hepatic and pancreatic branches of the celiac trunk are the primary sources of blood supply to the duodenum. The superior and inferior mesenteric arteries supply the blood to the duodenum through the jejunum and ileum.
• The duodenum is innervated by the autonomic nervous system. The parasympathetic nervous system innervates the duodenum through the vagus nerve. The sympathetic nervous system innervates the duodenum through the celiac ganglion.

Functions of Duodenum

• The duodenum is a section of the small intestine that is responsible for the digestion of food.
• The duodenum contains digestive enzymes that break down food into smaller pieces that can be absorbed by the body.
• It also absorbs nutrients from food and helps to move food through the digestive system.