Small Intestine Flashcards
What are the 3 parts of the small intestine?
Duodenum
Jejunum
Ileum
What is the jejunum?
Direct continuation of the duodenum
How much of the small intestine is the jejunum?
Jejunum accounts for first 3/5 of small intestine
What is the Ileum?
Latter 2/5 of small intestine
Terminates at Ileocaecal junction
What structure makes it hard to see the duodenum?
Jejunum, Ileum and mesocolon
Where does the Duodenum start and terminate?
Begins at pylorus terminates at sharp duodenal-jejunal flexure
Which structure lies in close relation to the duodenum?
Head of the pancreas
- allows secretion of pancreatic juices via pancreatic duct
- common bile duct also drains
=> ampulla of vater
Why is the duodenum placed posteriorly in the abdominal cavity compared to the other GI structures?
Due to rotation of the midgut during embryological development
Which vessels supply blood to the small intestine through the mesentery?
Superior mesenteric artery branches
Describe the difference in artery branches towards to jejunum and ileum
Organised in cascades
Jejunum (proximal) single arcades
Multiple larger cascades towards ileum
More fat contained distally
What is the role of the jejunum?
Absorbs nutrients from digested food into bloodstream
What is the function of the Ileum?
Absorb Vit.B12, bile salts and remaining nutrients not absorbed via jejunum
How does the jejunum and ileum differ?
Ileum is thinner walled, narrower and less vascular
What does the mesentery contain?
Provides lymphatics, veins, arterial and nervous supply
What is the mesentery attached to?
Posterior abdominal wall ending close to the caecum
