Small Intestine

Question 1

lymph drainage of the jej and ileum

Answer 1

superior mesenteric nodes.

Question 2

vein drainage of the jej and ileum

Answer 2

The venous drainage is via the superior mesenteric vein. It unites with the splenic vein at the neck of the pancreas to form the hepatic portal vein.

Question 3

arterial suply of the jej and ilieum

Answer 3

The arterial supply to the jejunoileum is from the superior mesenteric artery.

The superior mesenteric artery arises from the aorta at the level of the L1 vertebrae, immediately inferior to the coeliac trunk. It moves in between layers of mesentery, splitting into approximately 20 branches. These branches anastomose to form loops, called arcades. From the arcades, long and straight arteries arise, called vasa recta.

Question 4

arterioal supply of the duodenum

Answer 4

Proximal to the major duodenal papilla – supplied by the gastroduodenal artery (branch of the coeliac trunk).
Distal to the major duodenal papilla – supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery).

Question 5

why is there a change in blood supply between the duodeum

Answer 5

it marks the change from the embryological foregut to midgut.

Question 6

veinage drainage of the duodenum

Answer 6

veins of the duodenum follow the major arteries and drain into the hepatic portal vein.

Question 7

what attaches the jej and il to the post abdo wall

Answer 7

mesentery

Question 8

where does the jej begin

Answer 8

duodenojejunal flexure

Question 9

where does the ileum end

Answer 9

ileoceal junction

Question 10

what happens at the ileoceal junction

Answer 10

the ileum invaginates into the cecum to form the ileocecal valve.

Question 11

whats the deal with tthe ileoceacal valve?

Answer 11

it is not developed enough to control movement of material from the ileum to the cecum, it can prevent reflux of material back into the ileum

Question 12

what does the duodenum wrap around

Answer 12

the head of the pancreas.

Question 13

what is located at the duodenojejunal junction

Answer 13

slip of muscle called the suspensory muscle of the duodenum. Contraction of this muscle widens the angle of the flexure, and aids movement of the intestinal contents into the jejunum.

Question 14

descibe the three sections of the duodenum

Answer 14

Superior (L1)

The first section of the duodenum (‘the cap’) is 5cm in length. It ascends upwards from the pylorus of the stomach, and is connected to the liver by the hepatoduodenal ligament. This area is most common site of duodenal ulceration.

The initial 3cm of the superior duodenum is covered anteriorly and posteriorly by visceral peritoneum, with the remainder retroperitoneal (only covered anteriorly).

Descending (L1-L3)

The descending portion curves inferiorly around the head of the pancreas. It lies posteriorly to the transverse colon, and anterior to the right kidney.

Internally, the descending duodenum is marked by the major duodenal papilla – an opening for bile and pancreatic secretions to enter. The duct responsible carrying these secretions is known as the ampulla of Vater (hepatopancreatic ampulla).

Inferior (L3)

The inferior duodenum travels laterally to the left, crossing over the inferior vena cava and aorta. It is located inferiorly to the pancreas, and posteriorly to the superior mesenteric artery and vein.

Ascending (L3-L2)

After the duodenum crosses the aorta, it ascends and curves anteriorly to join the jejunum at a sharp turn known as the duodenojejunal flexure.

Question 15

difference between jejunum and ilium

Answer 15

Jej

• longer vasa recta
• less archades
• thick intestinal wall
• red
• upper left quadrant

ilium

• located in the lower right quad
• thin intestinal wall
• shorter vasa reca
• more arcades
• pink