Duodenum
Structure and Function
Structure
Functions
Arterial and Venous supply
Nervous Supply
The nerves are derived from sympathetic and parasympathetic (vagus) nerves from the celiac and the superior mesentery plexi.
Lymph
The vessels follow the arteries and drain upwards via pancreatoduodnenal nodes to the gastroduodenal nodes, then the celiac nodes. They drain downwards via the pancreatoduodenal nodes to the superior mesentery nodes (near the start of the artery).
Histology
The epithelium contains goblet cells and endocrine cells between enterocytes. Directly underneath that are the ECL (Enterochromaffin-like cells) and paneth cells. At the bottom of the villi, tubular glands and crypts extend down to the muscularis mucosa. The glandular cells tend to be scarce on the the villi and to confederate in the crypts. In the submucosa are the brunner's glands. The lamina propria contains cellular infiltrates.
Key:
- Goblet cells secrete mucus.
- Endocrine secrete enteroglucagon, CCk, secretin, motilin, gastrin.
- ECLs secrete serotonin which regulates gut motility and blood supply.
- Paneth cells secrete granules of antibacterial peptides.
- Brunner's glands secrete alkali mucus which neutralises gastric juice and epidermal growth factor, which promotes mucosal regeneration after injury.
- Lamina propria is made primarily of connective tissue, and contains the lacteal blood capillaries and cellular infiltrate (lymphocytes, mainly t helper ones, eosinophils, mast cells and plasma cells).
Clinical Conditions
Achalasia
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