Small Intestine Flashcards
What four segments does the duodenum consist of?
- superior part
- descending part
- horizontal part
- ascending part
What flexures are there in the duodenum?
- superior duodenal flexure
- inferior duodenal flexure
- duodeno-jejunal flexure
About how long is the duodenum?
25-30 cm long
What organ does the duodenum enclose?
The head of the pancreas
Because of its appearance in radiographs, what can the superior portion of the duodenum also be called?
Ampulla or duodenal cap
The superior part of the duodenum is crossed posteriorly by two structures. Which?
The common bile duct and the portal vein. The inferior vena cava is deep to these structures.
Which parts of the duodenum is situated intaperitoneally and which are secondarily retroperitoneal?
The superior part is intraperitoneally and the rest is secondarily retroperitoneal structures (only anterior surfaces are covered by peritoneum).
The suspensory ligament (ligament of Treitz) connects which part of the duodenum to what structure?
It connects the ascending part of the duodenum to the trunk of the superior mesenteric artery
What is the mucosa in the duodenum like?
It has densely packed, tall circular folds (Kerckring valves/folds). They consist of mucosa and submucosa
In which part of the duodenum can you find the longitudinal fold of the duodenum?
Descending part of the duodenum
Where does the bile duct and the pancreatic duct open into the duodenum?
The major duodenal papilla in the descending duodenum.
What opens into the minor duodenal papilla?
Accessory pancreatic duct
How big part of the small intestine does the jejenum and ileum consist?
Jejenum: two fifths
Ileum: three fifths
From where to where does the root of the mesentery go? How long is it?
From the duodeno-jejunal flexure to the right iliac fossa. 15-18 cm
Is the ileum and jejenum intraperioneally or not?
Yes, they are.
What is a Meckel dioverticulum?
It is a remnant of the embryonic Vitelline duct. In about 2% of humans there is a blind pouch of the ileum located 50-100 cm from the ileocecal valve.
How can you distinguish the ileum and jejenum from each other macroscopically?
You cannot
In the ileum there are mucosal bulges in the lumen opposite of the mesenteric attachment. What is this?
Aggregated lymphoid nodules (Peter patches) in the mucosa and submucosa.
What are the arteries supplying the duodenum? And which arteries do they branch from?
Celiac trunk -> common hepatic artery -> gastroduodenal artery -> anterior superior pancreaticoduodenal artery and anterior posterior pancreaticoduodenal artery
Superior mesenteric artery -> inferior pancreaticoduodenal artery
The anterior superior pancreaticoduodenal artery, anterior posterior pancreaticoduodenal artery and inferior pancreaticoduodenal artery form a vascular loop.
Through which veins does the duodenum drain?
Splenic vein and superior mesenteric vein
What is the innervation of the duodenum?
Extrinsic: nerve plexuses along the mesenteric vessels.
Parasympathetic: vagal trunks
Sympathetic: celiac ganglia and superior mesenteric ganglion
Which arteries gives blood supply to the jejenum and ileum?
Branches of the superior mesenteric artery give about 4-5 jejunal arteries and abut 12 ileal arteries
Nerve innervation of the jejenum and the ileum
Extrinsic: nerve plexuses along the mesenteric vessels.
Parasympathetic: vagal trunks
Sympathetic: celiac ganglia and superior mesenteric ganglion
