Small Intestine Anatomy

Small Intestine Characteristics

• The small intestine is 2.5cm wide and 6m long, occupying most of the abdominal space.

Small Intestine Structure

• The small intestine has three parts: duodenum, jejunum, and ileum.
• It begins at the pyloric sphincter and ends with its connection to the large intestine at the ileocaecal valve.

Duodenum Functions

• The duodenum is primarily responsible for breaking down food in the small intestine using enzymes.
• Brunner's glands, which secrete mucus, are found in the duodenum.
• The duodenum wall consists of a thin layer of cells that form the muscularis mucosae.
• The duodenum is almost entirely retroperitoneal.

Duodenum Regulation

• The duodenum regulates the rate of emptying of the stomach via hormonal pathways.
• Secretin and cholecystokinin are released from cells in the duodenal epithelium in response to acidic and fatty stimuli.
• These hormones are released when the pylorus opens and releases gastric chyme into the duodenum for further digestion.

This quiz covers the structure and functions of the small intestine, including its three parts: duodenum, jejunum, and ileum. Learn about the breakdown of food and the role of enzymes and Brunner's glands.