Anatomy and Physiology of the Duodenum

Overview

Length and Shape: The duodenum is 25-30 cm long, C-shaped, and located around the head of the pancreas at the L1-L3 vertebral levels.
Function: Receives partially digested food from the stomach, initiates nutrient absorption, and neutralizes stomach acid.
Sections:
- Superior Part: Connects to the stomach's pylorus; located intraperitoneally.
- Descending Part: Receives bile and pancreatic juices; contains major and minor duodenal papillae.
- Horizontal Part: Extends between the aorta and inferior vena cava.
- Ascending Part: Connects to the jejunum; attached to the posterior abdominal wall by the ligament of Treitz.

Layers:
- Mucosa: Contains enterocytes, goblet cells, and endocrine cells.
- Submucosa: Houses Brunner's glands and Meissner's plexus.
- Muscularis: Composed of inner circular and outer longitudinal layers with the Auerbach’s plexus.
Characteristic Features:
- Brunner's glands produce alkaline mucus to neutralize gastric acid.
- Crypts of Lieberkühn and Paneth cells play a role in antimicrobial defense.

Neutralization: Produces alkaline secretions to neutralize stomach acid.
Digestion: Mechanically processes and digests chyme.
Absorption: Absorbs water, electrolytes, and nutrients, particularly water-soluble substances.
Enzyme Mixing: Mixes bile and pancreatic enzymes to aid digestion.

The ligament of Treitz marks the division between the upper and lower gastrointestinal tracts.

Suggested video: "Duodenum" (23:05) for visual learning.
Quizzes available to test knowledge on the duodenum and other digestive system structures.

Referenced academic literature and peer-reviewed research ensure the reliability of information.
Visual aids include illustrations and diagrams for better understanding.

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