Anatomy Bones and Muscles · MU Pleven

54. Duodenum

Covers the duodenum within the small intestine: its position at vertebral levels L1 to L3, its length, and its C-shaped course. It then goes through the four parts, D1 to D4, with their lengths and relations to the kidney, pancreas and vertebrae, noting which parts are secondarily retroperitoneal. Blood supply, venous and lymphatic drainage, and innervation follow, and the note closes with a brief contrast between the jejunum and ileum.

Inside: 11 sections · 6 labelled pictures · 16 flashcards · 4 min

Topic 53 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 10 sections, about 540 words (4 min of reading), with 16 flashcards.

In this note

  1. SMALL INTESTINE
  2. Parts :
  3. Fixation :
  4. Histology :
  5. DUODENUM
  6. Blood supply:
  7. Innervation:
  8. JEJUNM & ILEUM
  9. Jejunum:
  10. Ileum:

SMALL INTESTINE

  • The small intestine is the longest part of the digestive system.
  • Approximately 3-5 m long and its width is 2-4 cm

* Is the primary site for absorption of nutrients from ingested material.

  • Extends from the pylorus of the stomach to the ileocaecal junction

Parts :

  1. (1) Duodenum
  2. (2) Jejunum
  3. (3) Ileum

Fixation :

The small intestine is fixed and supported within the abdominal cavity by several structures, preventing excessive movement and ensuring proper function.

  1. 1. Mesentery : double layer fold of the peritoneum

The small intestine is connected to the posterior abdominal wall by it.

  1. 2. Root of menestry:
  • the attachment of the mesentery to the posterior abdominal wall
  • extends from the duodenojejunal flexure to the right iliac fossa.

Histology :

4 layers:

  1. 1. Mucosa: lined by Simple columnar epithelium. with valve
  2. 2. Submucosa: Connective tissue layer
  3. 3. Muscular Externa : smooth muscle layer
  • inner (circular) ↔ outer (longitudinal)
  1. 4. Serosa.

DUODENUM

  • Originates at the pyloric orifice, continues into the jejunum at the duodenojejunal flexure.
  • Located at the level of L1 - L3
  • It length about 25 - 30 cm
  • Fixed (retroperitoneal)
  • C - shaped.

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