Block 6 Anatomy Duod Liv Panc Livr Glblder Umich W Expl

The gastroduodenal artery is a branch of the common hepatic artery--it passes immediately posterior to the first portion of the duodenum, and it can be damaged if there is an ulcer in this part ot the duodenum. The cystic artery supplies the gall bladder--it can be located in the triangle of Calot. The proper hepatic artery is a branch of the common hepatic artery--it travels superior to the first portion of the duodenum. The left gastric artery is a branch of the celiac trunk--it supplies the left side of the lesser curvature of the stomach.

The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and the passage of food will be obstructed. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum. Take a look at Netter Plate 292 for an illustration of the third part of the duodenum lying between these important vessels.

The orally ingested contrast medium would coat all the structures of the gut tube, including the esophagus, stomach, duodenum, and colon. The medium should go anywhere that ingested food might go in the GI tract. The gallbladder, however, is not a part of the passageway for food - it concentrates and secretes stored bile. So, the gall bladder would not be filled with contrast.

The gastroduodenal artery lies behind the superior part of the duodenum. It has three branches: the posterior superior pancreaticoduodenal artery, the anterior superior pancreaticoduodenal artery, and the right gastroomental artery. The other vessels are not near the superior duodenum. The coronary vein is made of the right and left gastric veins and located in the lesser curvature of the stomach. The inferior pancreatoduodenal arcade is found in the inferior part of the head of the pancreas. It supplies the pancreas and duodenum. It is near the horizontal (3rd) part of the duodenum, not the superior part. The proper hepatic artery is a branch of the common hepatic artery which delivers oxygenated blood to the liver. Finally, the splenic vein comes from the spleen--it joins the superior mesenteric vein to form the portal vein.

A Kocher maneuver involves reflecting the duodenum and pancreas medially by cutting through the fusion fascia along the right side of the descending part of the duodenum. This technique is used to gain access behind the pancreas. However, even if you didn't know the exact definition of a Kocher maneuver, you could still answer this question. The question is asking you to pick which organ is secondarily retroperitoneal, and the only secondarily retroperitoneal organ listed is the duodenum. The kidney and suprarenal gland were retroperitoneal during the entire developmental process, and the transverse colon and spleen are peritonealized. So, duodenum is the only answer that makes sense here.

The splenic vein is a major vein of the portal system, while the left renal vein is a major vein of the caval system. These veins are large, so a bypass between them could be useful for relieving the portal hypertension. The coronary vein, right gastroepiploic vein, inferior mesenteric vein, splenic vein, left colic vein, middle colic vein, and superior mesenteric vein are all part of the portal system. Any bypasses among these veins will not relieve the portal hypertension.

Like the left hepatic vein, the left hepatic duct drains bile from the left lobe, quadrate lobe, and part of the caudate lobe of the liver. So, an obstruction in the quadrate lobe would reduce bile secretion in the left hepatic duct. The right hepatic duct and hepatic vein drain the right lobe and part of the caudate lobe.

The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and food won't be able to pass through the duodenum. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum. Take a look at Netter Plate 292 for an illustration of the third part of the duodenum lying between these important vessels. You should know what structures are involved in the "nutcracker effect" and how they are causing an upper bowel obstruction!

Tumors in the head of the pancreas often obstruct the common bile duct, blocking the normal bile recycling circuit. This blockade prevents excretion of bilirubin, a yellow-colored pigment that is a red blood cell breakdown product. The accumulation of bilirubin in various tissues, including the skin, causes jaundice. Tumors in other areas of the pancreas are not as likely to block the common bile duct and cause jaundice.

Tumors in the head of the pancreas often obstruct the common bile duct, blocking the normal bile recycling circuit. This blockade prevents excretion of bilirubin, a yellow-colored pigment that is a red blood cell breakdown product. The accumulation of bilirubin in various tissues, including the skin, causes jaundice. A tumor in the head of the pancreas would not block the other ducts--look at Netter 276 to see how all the ducts are related.

This question is asking you to identify the organ that is secondarily retroperitoneal. This means that it started out peritonealized but became pressed against the posterior body wall and stuck there during development. Except for the first few centimeters of the superior segment and the duodenojejunal junction, the duodenum is a secondarily retroperitoneal organ - it used to have a mesentery, but that was lost during gut rotation. Although the kidney is a retroperitoneal organ, it is not secondarily retroperitoneal - it started developing in the retroperitoneum and stayed there. The spleen, stomach, and transverse colon are all peritonealized. What segments of the colon are peritonealized? The cecum, transverse colon, and the sigmoid colon are peritoneal, but the ascending and descending colon are retroperitoneal.

The first part of the duodenum features thin walls and no circular folds. It is called the ampulla of the duodenum. Once the duodenum turns and becomes the second part, the walls become thicker, and circular folds develop. The second part of the duodenum has the hepatopancreatic ampulla in its medial wall, which is the duct formed as the common bile duct and pancreatic duct join to empty their secretions into the duodenum. The transverse colon overlies the second part of the duodenum, and the second part of the duodenum is a secondarily retroperitoneal organ. Also, remember that the anterior and posterior superior pancreaticoduodenal arteries are branches of the gastroduodenal artery, which receives blood from the celiac trunk. The anterior and posterior inferior pancreaticoduodenal arteries receive blood from the superior mesenteric artery.

The hepatopancreatic ampulla is the very short segment of duct which represents the joining of the common bile duct and the main pancreatic duct. Once these two ducts form the hepatopancreatic ampulla in the wall of the duodenum, the bile and pancreatic enzymes are emptied into the second portion of the duodenum, through the major duodenal papilla. If a gallstone was stuck in the hepatopancreatic ampulla, bile could back up and flow backwards into the main pancreatic duct. If a stone was lodged in the cystic duct, common hepatic duct, or common bile duct, bile would never even reach the pancreas. See Netter Plate 276 for an illustration.

The splenic vein is a major vein of the portal system, while the left renal vein is a major vein of the caval system. These veins are large, so a bypass between them could be useful for relieving the portal hypertension. The coronary vein, right gastro-omental vein, left colic vein, sigmoidal vein, inferior mesenteric vein, and splenic vein are all part of the portal system. Any bypasses among these veins will not relieve the portal hypertension. The superior and inferior rectal veins already form a portal-caval anastomosis; surgery would not be needed to connect these two venous channels. However, if too much blood tries to flow through this anastomosis, hemorrhoids will develop. These veins are not large enough to help relieve severe portal hypertension.

The left and right hepatic arteries help support the parenchyma and stroma of the liver. The left hepatic artery supplies the left & quadrate lobes of liver, and part of the caudate lobe. The right hepatic artery supplies the right lobe and part of the caudate lobe. So, the left hepatic artery must be clamped to perform surgery on the quadrate lobe.

The gastroduodenal artery is the artery that has ruptured. This artery gives off the anterior and posterior superior pancreatoduodenal arteries, which supply the first and second parts of the duodenum, as well as the head of the pancreas. The gastroduodenal artery also gives off the right gastroomental artery, which supplies the right half of the greater curvature of the stomach. In contrast, the tail of the pancreas is supplied by the caudal pancreatic artery, which is a branch of the splenic artery. It would not be affected by damage to the gastroduodenal artery.

The triangle of Calot is formed by the cystic duct laterally, the liver superiorly, and the common hepatic duct medially. It is an important landmark in this region, because the cystic artery can be found in the triangle of Calot. During a cholecystectomy, the cystic artery needs to be ligated. Although the cystic artery usually branches from the right hepatic artery, there is some variation. However, if you locate the triangle of Calot, you can find the cystic artery in that triangle, trace it back to its origin, and then ligate it there.

The superior mesenteric artery crosses over the third part of the duodenum, and the aorta is posterior to the third part of the duodenum. If something causes these vessels to become enlarged, they can crush the duodenum, and food will not be able to pass through the duodenum. This is often called the "nutcracker effect," and it is only seen in the third part of the duodenum. Take a look at Netter Plate 292 for an illustration of the third part of the duodenum lying between these important vessels.

The duodenum receives blood from the gastroduodenal artery, a branch of the common hepatic artery. It also receives blood from the inferior pancreatoduodenal artery, which is a branch of the superior mesenteric artery. So, the duodenum is receiving blood from the common hepatic artery and the superior mesenteric artery, but it is not receiving any blood from the splenic artery.
The splenic artery supplies blood to the body of the pancreas with the dorsal and superior pancreatic arteries; it supplies blood to the tail of the pancreas with the caudal pancreatic artery. The splenic artery supplies the fundus of the stomach with short gastric arteries and the left portion of the greater curvature with the left gastroomental artery. The left gastroomental artery also supplies blood to the greater omentum through omental branches. All of these structures would be affected if the splenic artery was ligated.

The superior part of the duodenum is the one segment of the duodenum that has no circular folds. When food enters the duodenum from the pyloric sphincter, it enters the ampulla, which is a smooth area of the duodenum containing a high percentage of mucosal cells. These cells secrete mucus to neutralize the acidic contents of the stomach. If the stomach contents is not sufficiently neutralized, the thin wall of the ampulla may develop an ulcer. If the ulcer burns through the entire wall, it might jeopardize the gastroduodenal artery, lying behind the first segment of the duodenum. The descending, horizontal, and ascending portions of the duodenum all have circular folds. For an illustration of the different linings of the duodenum, see Netter Plate 262

The epiploic foramen, also called the omental foramen, is the passageway between the greater and lesser peritoneal sacs. The inferior vena cava lies immediately posterior to this foramen, so this is the vessel that was probably cut. The aorta lies next the inferior vena cava, but it is a little more to the left and a little deeper--it does not lie immediately posterior to the epiploic foramen. The hepatic portal vein is anterior to the epiploic foramen. The right renal artery is a branch off of the aorta. Like the aorta, it is too deep to be a vessel immediately behind the foramen. Finally the superior mesentric vein is anterior to the foramen. Remember, this is one of the two vessels that makes the hepatic portal vein, so if the hepatic portal vein is anterior to the foramen, the SMV should be too. (See Netter's 256 for some relevant pictures)

The inferior mesenteric vein usually empties into the splenic vein. The splenic vein and the superior mesenteric vein then unite to form the portal vein. Look at Netter Plate 290 for a picture of this. Remember--the inferior vena cava and left renal vein are caval veins--they are not involved in draining the gut.

This question is asking you to identify the structures that make the line that separates the true/functional lobes of the liver. The concept of functional lobes contrasts with traditional anatomical terminology, which separated the liver into the left, right, quadrate and caudate lobes. These traditional lobes were based on anatomical appearance, while the functional lobes are based on the distribution of the portal vein, hepatic arteries, and hepatic bile ducts. The functional lobes of the liver are separated into a right and left lobe by the gallbladder fossa and the inferior vena cava. So, the old "right lobe" corresponds to the functional right lobe, while the caudate, quadrate, and left lobes under anatomical terminology are lumped together as one big left lobe.

The pancreas is inferior to the superior portion of the duodenum, and the main pancreatic duct is found deep within the pancreas. It is not likely that this structure would be damaged by the duodenal ulcer. The portal vein, gastroduodenal artery, and the common bile duct all pass immediately deep to the first part of the duodenum. (The portal vein and common bile duct are associated with the proper hepatic artery, forming the portal triad.) These structures would all be at risk from the ulcer. See Netter Plate 279 for a picture illustrating this relationship.