Small Intestine

Question 1

What four segments does the duodenum consist of?

Answer 1

• superior part
• descending part
• horizontal part
• ascending part

Question 2

What flexures are there in the duodenum?

Answer 2

• superior duodenal flexure
• inferior duodenal flexure
• duodeno-jejunal flexure

Question 3

About how long is the duodenum?

Answer 3

25-30 cm long

Question 4

What organ does the duodenum enclose?

Answer 4

The head of the pancreas

Question 5

Because of its appearance in radiographs, what can the superior portion of the duodenum also be called?

Answer 5

Ampulla or duodenal cap

Question 6

The superior part of the duodenum is crossed posteriorly by two structures. Which?

Answer 6

The common bile duct and the portal vein. The inferior vena cava is deep to these structures.

Question 7

Which parts of the duodenum is situated intaperitoneally and which are secondarily retroperitoneal?

Answer 7

The superior part is intraperitoneally and the rest is secondarily retroperitoneal structures (only anterior surfaces are covered by peritoneum).

Question 8

The suspensory ligament (ligament of Treitz) connects which part of the duodenum to what structure?

Answer 8

It connects the ascending part of the duodenum to the trunk of the superior mesenteric artery

Question 9

What is the mucosa in the duodenum like?

Answer 9

It has densely packed, tall circular folds (Kerckring valves/folds). They consist of mucosa and submucosa

Question 10

In which part of the duodenum can you find the longitudinal fold of the duodenum?

Answer 10

Descending part of the duodenum

Question 11

Where does the bile duct and the pancreatic duct open into the duodenum?

Answer 11

The major duodenal papilla in the descending duodenum.

Question 12

What opens into the minor duodenal papilla?

Answer 12

Accessory pancreatic duct

Question 13

How big part of the small intestine does the jejenum and ileum consist?

Answer 13

Jejenum: two fifths
Ileum: three fifths

Question 14

From where to where does the root of the mesentery go? How long is it?

Answer 14

From the duodeno-jejunal flexure to the right iliac fossa. 15-18 cm

Question 15

Is the ileum and jejenum intraperioneally or not?

Answer 15

Yes, they are.

Question 16

What is a Meckel dioverticulum?

Answer 16

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.

Question 17

How can you distinguish the ileum and jejenum from each other macroscopically?

Answer 17

You cannot

Question 18

In the ileum there are mucosal bulges in the lumen opposite of the mesenteric attachment. What is this?

Answer 18

Aggregated lymphoid nodules (Peter patches) in the mucosa and submucosa.

Question 19

What are the arteries supplying the duodenum? And which arteries do they branch from?

Answer 19

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.

Question 20

Through which veins does the duodenum drain?

Answer 20

Splenic vein and superior mesenteric vein

Question 21

What is the innervation of the duodenum?

Answer 21

Extrinsic: nerve plexuses along the mesenteric vessels.
Parasympathetic: vagal trunks
Sympathetic: celiac ganglia and superior mesenteric ganglion

Question 22

Which arteries gives blood supply to the jejenum and ileum?

Answer 22

Branches of the superior mesenteric artery give about 4-5 jejunal arteries and abut 12 ileal arteries

Question 23

Nerve innervation of the jejenum and the ileum

Answer 23

Extrinsic: nerve plexuses along the mesenteric vessels.
Parasympathetic: vagal trunks
Sympathetic: celiac ganglia and superior mesenteric ganglion