Duodenum, Small Intestine Flashcards
What is responsible for suspension of the duodenojejunal flexure?
the suspensory ligament of the duodenum (ligament of Treitz)
What is the ampulla of Vater?
segment where the path of the bile duct and the main pancreatic duct are shared before entering the 2nd part of the duodenum
What marks the transition between the foregut and the midgut?
the major duodenal papilla
What is the sphincter of Oddi?
a muscular sphincter surrounding the major duodenal papilla
The jejunum and ileum are connected to the posterior abdominal wall via what?
the mesentery proper and they are therefore intraperitoneal
What is McBurney’s point?
roughly approximates the position of the ileocecal junction and is used during physical exam to diagnose appendicitis (in response to pressure applied at this point)McBurney’s point lies on a straight line drawn between the anterior superior iliac spine (ASIS) and the umbilicus and divides the line into its inferior 1/3 and superior 2/3.
What are the two structures caught in the nutcracker relationship formed by the acuteangle between the SMA and the abdominal aorta?
The left renal vein and the 3rd part of the duodenum
What is Nutcracker syndrome?
entrapment of the L renal vein. Entrapment of the duodenum is called superior mesenteric artery syndrome and is very rare.
Blood supply proximal to the duodenal papilla is from what?
the celiac trunkDistal to the papilla, the blood supply is from the superior mesenteric artery.
What part of the pancreas lies anterior to the SMA and SMV?
the neck
The tail is the continuation of the body into what?
the lienorenal ligament. As such, it is the only part of the pancreas that is peritoneal.
The jejunum comprises the proximal ___ of the small intestine; the ileum comprises the distal ___ of the small intestine
2/5; 3/5
Why is it not necessary true that loops of jejunum are always higher in the abdominal cavity than loops of ileum?
Both are quite mobile in the abdomenWhat is true is that the root of the mesentary of the jejunum is on the left side of the midline and that of the ileum is to the right of the midline.
Which has thicker walls, the jejunum or the ileum?
jejunum (more absorptive surface)
Which has a larger diameter lumen, the jejunum or the ileum?
jejunum
Which has longer straight arteries, the jejunum or the ileum?
jejunum
Which has more mesenteric fat, the jejunum or the ileum?
ileum
Which has more elaborate circular mucosal folds (Plicae circulares), the jejunum or the ileum?
jejunum
Which has more prominent/complex arterial arcades, the jejunum or the ileum?
ileumNote that there are one or two tiers of anastomotic arches in the mesentary of the jejunum whereas there are up to five or size levels of arterial arches in the mesoileum.
The Right Colic Flexure is aka?
The Hepatic Flexure
The Left Colic Flexure is aka?
The Splenic Flexure
The presence of tenia coli and haustra in the large intestine are due to what?
due to uneven distribution of smooth muscle in the wall of the colon
Notes on haustra
They are due to uneven distribution of the circular smooth muscle layer. Where there is a concentration of circular smooth muscle, the diameter of the colon is narrowed. This is the narrow part between each haustra.
Notes on tenia coli
Tenia coli are due to uneven distribution of the longitudinal smooth muscle layer. The longitudinal smooth muscle is concentrated in the tenia colie so that the exterior of the colon there is made smooth. The tenia coli have been likened to a shiny highway running length of the colon. There are three tenia coli.
What parts of the colon are peritoneal?
transverse and sigmoid
The transverse colon is at what vertebral level?
transpyloric plane
What are the main branches off the superior mesenteric artery?
A. Inferior pancreaticoduodenal aa. B. Intestinal aa. (jejunal and ileal aa.) C. Middle colic a.D. Right colic a.E. Ileolcolic a.
What are the main branches off the inferior mesenteric artery?
A. Left colic a.B. Sigmoidal aa.C. Superior rectal a.
The marginal artery is an anastomotic loop along in interior margins of the colon. It is made up of the branches of what arteries?
the right, middle, and left colic aa. and the sigmoidal aa.
T or F. The origin of the IMA lies posterior to the third part of the duodenum
TWith respect to surface anatomy, the origin of the IMA and the third part of the duodenum lie 2 cm (3/4”) above the transumbilical plane. The bifurcation of the abdominal aorta into R & L common iliac arteries lies the same distance, 2 cm, below the transumbilical plane.
T or F. The tributaries of the superior and inferior mesenteric veins have the same names and pattern as the branches of the SMA and IMA
T
What is the portal vein is defined as?
being formed by the junction of the SMV and splenic vein (that’s why it is aka the splenic-mesenteric confluence). This junction lies in the transpyloric plane, posterior to the neck of the pancreas.NOTE: the veins corresponding to primary branches of the celiac trunk, notably the L & R gastric veins, the L & R gastroepiploic veins and the splenic vein are direct tributaries to the portal vein
