Upper GI Tract Flashcards
What structure divides the abdominal cavity from the pelvic cavity?
This is a trick question, there is no separation. The two cavities are continuous.
What diaphragms serve as the boundaries of the abdominalpelvic cavity?
Superiorly-the respiratory diaphragm
Inferiorly- the pelvic diaphragm
Describe the imaginary plane that separates the abdominal cavity from the pelvic cavity.
The imaginary plane is drawn from the superior anterior portion of the sacrum to the pubis anteriorly.
What 3 important structures are transmitted through diaphragmatic hiatuses?
- Inferior Vena cava (8)
- Aorta (12)
- Esophagus (10)
What other 2 structures may also pass through the aortic hiatus at vertebral level T12?
- The thoracic duct
2. Azygous vein
Mnemonic: I ate 10 eggs at 12
This mnemonic helps you remember the vertebral level at which specific structures pass through their diaphragmatic hiatus to enter the abdominal cavity.
I 8: inferior vena cava @T8
10 Eggs: esophagus @ T10
At 12: aorta @T12
What is the name for the small arteries that travel along the inferior surface of the diaphragm and contribute to the blood supply of the diaphragm?
Inferior phrenic arteries
If you open the abdominal wall from an anterior view, what structures would you see?
- Liver
- Stomach
- A small portion of the small intestine
- Greater omentum
What layer of peritoneum covers the organs in the peritoneal cavity?
Visceral peritoneum
Where would the parietal peritoneum of the peritoneal cavity be located?
Parietal peritoneum can be found covering the internal aspect of the abdominal wall.
When you remove the abdominal wall, containing the parietal peritoneum, and view the abdominal structures, covered by visceral paritoneum, what space is being examined (the answer is NOT the abdominal cavity)?
Peritoneal cavity.
The peritoneal cavity is dividing into two different spaces, what are they?
- Greater sac
2. Lesser sac
Where is the greater sac of the peritoneal cavity?
The greater sac is the area that lies on top of AND under the greater omentum.
If you remove the greater omentum and placed your hand on top of the colon or small intestine, is your hand still located in the greater sac?
Yes, the colon is also covered by visceral peritoneum. This, if your hand is under the greater omentum but still on top of the colon you are still within the greater sac of the peritoneal cavity.
Where is the lesser sac of the peritoneal cavity located? What is it’s function?
The lesser sac is located posterior to the stomach.
The lesser sac is an area into which the stomach may expand.
Which omentum is associated with the greater curvature of the stomach?
Greater omentum
Which omentum is associated with the lesser curvature of the stomach?
Lesser omentum
The lesser omentum lies between which two organs?
Stomach (attached to the lesser curvature) and the liver
Name the opening on the right border of the lesser omentum that grants access to the space posterior to the stomach (lesser sac).
Epiploic foramen (aka foramen of Winslow)
What is the alternative name for the foramen of Winslow?
Epiploic foramen
What is the alternative name for the epiploic foramen?
Foramen of Winslow
What three structures does the peritoneum form?
- Visceral pleura
- Parietal pleura
- Mesenteries (two layers of peritoneum)
What are the characteristic features of mesenteries?
- Formed by two layers of peritoneum
2. Contain neurovascular structures for the organs they are associated with
What other structures are considered mesenteries here at UCLA?
- Ligament
- Greater omentum
- Lesser omentum
What are the requirements for naming an abdominal structure “peritoneal”?
- The structure must have a named mesentery
2. It must be covered by peritoneum on more than one surface
What are the requirements for a structure to be considered “retroperitoneal”?
- It does not have a named mesentery.
2. There is not a peritoneum on more than one surface
Do retroperitoneal structures need mesenteries?
No. This structures grow right on top of the posterior abdominal wall (pancreas) or on the lateral part of the abdominal wall (ascending and descending colon). Their neurovascular supply can reach them from behind.
Stomach, Liver, transverse colon. Are these structures peritoneal or retroperitoneal?
Peritoneal.
Stomach & liver: surrounded by peritoneum and has named mesentery (hypogastric ligament and greater omentum
Transverse colon: peritoneum and mesentery
Pancreas, ascending colon, descending colon. Retroperitoneal or peritoneal?
Retroperitoneal.
These structures do not need a mesentery as their neurovascular supply can reach them from behind the peritoneum
Where is the pancreas?
Behind the peritoneum, just anterior to the aorta and vena cava.
What six mesenteries are we responsible for knowing here at UCLA?
- Greater omentum
- Lesser omentum
- The Mesentery
- Mesoappendix
- Transverse mesocolon
- Sigmoidal mesocolon
What is an alternative name for the greater omentum?
Gastrocolic ligament
How many layers can the greater omentum have? Why is this?
4 layers because it extends from the inferior portion of the stomach and then turns up superiorly to travel to the colon.
Does the greater omentum always have 4 layers?
No. At some portions there are only two layers as is characteristic of a traditional mesentery.
Name the two subligaments of the lesser omentum.
- Hepatogastric ligament
2. Heptoduodnal ligament
What structures does the lesser omentum attach to?
Stomach, liver and first part of the small intestine (duodenum)
If you lift the greater omentum and pull the small intestine anteriorly, what three mesenteries have you uncovered?
- The Mesentery
- Mesoappendix
- Transverse mesocolon
Which mesentery is barely visible and contains neurovasculature that serves the appendix?
Mesoappendix
Which mesentery contains the most neurovasculature that serves the small intestine?
The Mesentery
Which mesentery contains neurovasculature that serves the transverse colon?
Transverse mesocolon
Which mesentery serves the ascending colon?
Trick question: The ascending and descending mesocolon DO NOT have named mesenteries. These structures receive their neurovascular supply from behind the peritoneum. They are retroperitoneal.
If you remove the greater omentum, and completely remove all of the small intestine, which mesentery had been uncovered?
Sigmoid mesocolon
Which mesentery serves the descending colon?
Trick question: The ascending and descending mesocolon DO NOT have named mesenteries. These structures receive their neurovascular supply from behind the peritoneum. They are retroperitoneal structures.
Which mesentery contains neurovascular structures that serve the sigmoid colon?
Sigmoid mesocolon
Name the 3 subdivisions of the gut tube?
- Foregut
- Midgut
- Hindgut
How are the three divisions of the gut tube supplied with blood and innervated?
Each division has it’s own large aortic branch to supply blood and it’s own visceral plexus to supply autonomic innervation.
What is the major aortic branch and nerve supply for the foregut?
Celiac trunk; celiac plexus
What structures comprise the foregut?
Stomach, duodenum (first two segments)
What associated organs comprise the foregut?
Liver, gallbladder, pancreas(also shared with midgut), spleen abdominal esophagus (blood suppy only)
Which mesentery contains the most neurovasculature and serves the small intestine?
The Mesentery
Which mesentery is barely visible and contains neurovasculature that serves the appendix?
Mesoappendix
Which mesentery contains the neurovasculature that serves the transverse colon?
Transverse mesocolon
Which mesentery serves the ascending colon?
Trick question: The ascending and descending mesocolon DO NOT have named mesenteries. These structures receive their neurovascular supply from behind the peritoneum.
Which mesentery serves the descending colon?
Trick question: the ascending and descending mesocolon DO NOT have named mesenteries. These structures receive their neurovascular supply from behind the peritoneum. They are retroperitoneal structures.
If you remove the greater omentum, and completely remove all of the small intestine, which mesentery had been uncovered?
Sigmoid mesocolon
Which mesentery contains neurovascular structures that serve the sigmoid colon?
Sigmoid mesocolon
Name the 3 subdivisions of the gut tube?
- Foregut
- Midgut
- Hindgut
How are the three divisions of the gut tube supplied with blood and innervated?
Each division has it’s own large aortic branch to supply blood and it’s own visceral plexus to supply autonomic innervation.
What is the major aortic branch and nerve supply for the foregut?
Celiac trunk; celiac plexus
What structures comprise the foregut?
Stomach, duodenum (first two segments)
What associated organs share neurovascular supply with the foregut?
Liver, gallbladder, pancreas(also shared with midgut), spleen abdominal esophagus (blood suppy only)
Name the 3 main branches of the celiac trunk.
- Common hepatic artery
- Left gastric artery
- Splenic artery
Where is the celiac plexus located?
On the surface of the celiac trunk and it’s branches
Which type of fibers travel through the celiac plexus and synapse ON GANGLIA located IN THE WALLS OF THE TARGET ORGAN?
VE para/pre fibers from the vagus nerve (CN X).
Remember: upper GI organs receive their parasympathetic innervation from the vagus nerve. Also, parasympathetic fibers are long and synapse in ganglia in or near the target organ. While sympathetic fibers synapse in ganglia outside of the target organ.
Describe the sympathetic innervation of the foregut.
Visceral efferent fibers synapse on the preaortic (celiac) ganglia. VE sym/post fibers then travel from these ganglia through the celiac plexus to arrive at their target organs in the foregut.
Describe the anatomical location of the stomach.
Underneath the diaphragm and the liver, on the left side of the body.
What is the function of the stomach?
Contribute to the chemical, mechanical and enzymatic digestion of food.
What plexus is responsible for the innervation of the stomach?
Celiac plexus
Remember: All foregut structures (stomach and first two sections of the duodenum) are innervated by the celiac plexus.
Name the two curvatures of the stomach, their location and the name of the mesentery associated with them.
- Greater curvature: The inferior margin of the stomach; attached to the greater omentum
- Lesser curvature: the superior margin of the stomach; attached to the lesser omentum
List the four parts of the stomach.
- Cardia
- Fundus
- Body
- Pylorus
Where is the cardiac sphincter located? What is it’s function?
In the cardia of the stomach; it allows the passage of food from the abdominal esophagus into the stomach
Where is the pyloric sphincter located? What is it’s function?
In the pylorus; allows food to enter the duodenum
What vessels contribute to the supply of blood to the stomach? NOTE: These are vessels that branch off of the celiac trunk or are branches of branches.
- Right and left gastric arteries and veins
- Right and left gastroepiploic arteries and veins
- Short gastric arteries and veins that branch from the splenic
The right gastric artery is a branch off of…
The proper hepatic artery
The left gastroepiploic artery is a branch of the _________ while the right gastroepiploic artery is a branch of the __________.
Splenic artery; gastroduodenal artery
Which of the following is NOT formed by the peritoneum: greater sac space, lesser sac space, mesentery, greater omentum or lesser omentum?
Trick question all of those structures are formed by the mesentery.
Which ligament of the lesser omentum is more opaque?
Hepatoduodenal ligament; the hepatogastric ligament is more clear
How is the esophagus innervated?
Same as the thorax and abdomen. 1.VE para/pre from CN X
2. VE sym/post from splanchnic nerves
In the abdomen, the esophagus shares it’s blood supply with what structure?
The stomach
Describe the blood supply of the abdominal esophagus.
It receives blood from the left gastric artery and vein
What innervates the abdominal esophagus?
The esophageal plexus
Which parts of the duodenum are peritoneal? Which parts are retroperitoneal?
Peritoneal: 1st and 4th part
Retroperitoneal: 2nd and 3rd parts
Where does the duodenum get it’s blood supply?
Superior Pancreaticoduodenal and inferior pancreaticoduodenal arteries and veins
What plexus is responsible for the innervation of the duodenum?
Celiac plexus
Why are pathologies between the pancreas and duodenum often interrelated?
The pancreas is nestled into the duodenum. The two organs share the same blood supply and thus are often affected as a pair.
Which 2 specific arteries serve their blood supply to the duodenum?
- Superior pancreaticoduodenal artery
2. Inferior pancreaticoduodenal artery
Which minor artery branches off into the superior pancreaticoduodenal artery?
The gastroduodenal artery (this is a branch of the common hepatic artery
Why does the duodenum have two blood supplies?
It is derived from both the foregut and the midgut. Thus, it has two different blood supplies.
The pancreatic duct shares an opening with which other duct?
The common bile duct; it opens into the duodenum
How is the pancreas innervated?
Like all associated organs of the foregut, it is innervated by the celiac plexus.
The pancreas has a rich blood supply from 2 main sources (celiac trunk and superior mesenteric artery). Name them.
From the celiac trunk:
- The superior pancreaticoduodenal artery
- Numerous small branches from the pancreatic branches of the splenic artery
From the superior mesenteric artery
3. Inferior pancreaticoduodenal artery
Why does the pancreas receive blood supply from both the celiac trunk and the superior mesenteric artery?
The pancreas is an accessory structure of the foregut, as well as, an organ of the midgut.
Upon removal of the spleen, which secondary GI organ will assume the functions previously done by the spleen?
The liver
If the spleen ruptures or begins to bleed profusely, what is the best treatment for a hypothetical patient?
Splenectomy (remove the spleen), the liver can assume the function of the spleen.
What is the function of the spleen?
- Lymphatic organ that provides immune surveillance for the blood
- removal of old RBCs from circulation
Where does the spleen get it’s blood supply?
Splenic artery
What plexus innervates the spleen? Be specific.
The splenic plexus via the celiac plexus
Describe the location of the spleen.
Inferior to the diaphragm on the left side of the body. Superior to the left colic flexure (splenic flexure).
Is the spleen peritoneal or retroperitoneal?
It is peritoneal. The spleen is surrounded by peritoneum.
Describe the location of the gallbladder.
Connected to the inferior surface of the liver
What is the function of the gallbladder?
The gallbladder stores and concentrates bile.
From which artery does the gallbladder receive it’s blood supply?
cystic artery
Name the three ducts of the gallbladder, their location and function.
- Common hepatic duct: route by which bile made in the liver flows into the cystic duct to reach the gallbladder
- Cystic duct: used ONLY by the gallbladder during secretion of bile into the common bile duct, or to allow the gallbladder to receive bile from the liver for storage
- Common bile duct: allows bile to reach the duodenum
Which gallbladder duct allows bile to reach the duodenum?
Common bile duct
Which gallbladder duct allows the gallbladder to receive and release bile?
cystic duct
Which gallbladder duct is used ONLY by the gallbladder?
Cystic duct
Which gallbladder duct connects the bile secretions of the liver to the gallbladder?
Common Hepatic Duct
Are the following organs peritoneal or retroperitoneal: spleen, gallbladder, liver
peritoneal
Describe the location of the liver.
Inferior to the diaphragm, on the right side of the body, superior to the hepatic flexure (right colic flexure).
Is the liver surrounded by peritoneum?
Yes, the liver is a peritoneal organ. It is surrounded by peritoneum and has two ligaments (mesenteries).
How many ligaments does the liver have? Name it/them.
3; Falciform ligament, ligamentumteres and coronary ligament
Name some of the functions of the liver.
- neutralizing toxins
- stores nutrients
- synthesizes a long range of products including bile
Which plexus innervates the liver? Be specific.
The hepatic plexus via the celiac plexus
The ligamentumteres is a remnant of what fetal structure?
the fetal umbilical vein
Which ligament of the liver is “sickle shaped”, and serves as a mesentery that attaches the liver to the anterior abdominal wall?
Falciform ligament
What shape is the falciform ligament?
sickle shaped
Which ligament of the liver is located in the inferior margin of the falciform ligament?
Ligamentumeres
Which ligamentum of the liver is a “crown-like ligament” and reflection of the peritoneum from the liver to the diaphragm anteriorly?
Coronary ligament
The lobes of the liver function nearly independent of each other because they have these three things individually:
- Blood supply
- Lymphatics
- Bile ducts
How many lobes can the liver be subdivided into?
4 lobes (grossly)
The falciform ligament separates which two lobes?
The right and left lobe
The right and left lobe of the liver can be viewed from which surface?
Anterior surface
The head of the gallbladder demarks which surface of the liver? Anterior or posterior?
Anterior (Think of the gallbladder as the liver’s penis. It hangs in the front and ejaculates stuff.)
Between the left and right lobe of the liver, which is smaller?
The left lobe
From an inferior view, which lobe of the liver is near the posterior portion of the liver superior to the gallbladder?
the caudate lobe
From an inferior view, which lobe of the liver is to the left of the gallbladder and near the anterior surface of the liver?
The Quadrate lobe
List the four lobes of the liver.
- Right lobe
- Left lobe
- Caudate lobe
- Quadrate lobe
What is the only lobe of the liver that lies to the left of the falciform ligament?
The left lobe
Clinical Question: You can remove a portion of the liver in a healthy subject without causing any medical issues. Why is this?
Each lobe of the liver has its own arterial supply, bile duct and lymphatic system. The lobes essentially function as individuals.
Through what mesentery does the portal triad travel?
The lesser omentum, strictly speaking the hepatoduodenal ligament of the lesser omentum.
What is the vein, artery and duct that comprises the portal triad?
- Proper hepatic artery
- Portal Vein
- Common bile duct
Why is it important that the portal triad consist of a vein that drains blood TO the liver as opposed to AWAY from the liver?
The liver is responsible for detoxifying the blood before it drains into general circulation. It achieves this function via the portal veins direct delivery of blood to the liver (first pass).
Is the portal traid really a triad?
No, in addition to the proper hepatic atery, portal vein and common bile duct there are also lymphatics and innervation.
30% of the livers blood supply comes from _______. The other 70% of the livers blood supply comes from _________.
Proper hepatic artery; portal vein
What is interesting about the blood supply to the liver, that you would not find in any other organ?
The majority (70%) of the liver’s blood is supplied via a vein (portal vein).
What is the portahepatis?
The portahepatis is a region on the inferior surface of the liver where the (1) hepatic duct, (2) proper hepatic artery and (3) portal vein interface with the liver.
Where does the (1) hepatic duct, (2) proper hepatic artery and (3) portal vein interface with the liver?
at the portahepatis on the inferior surface of the liver
Blood that is exiting the liver ultimately flows into what large vein?
the inferior vena cava (via several hepatic veins)
The portal vein drains blood from what structures into the abdominalpelvic area?
The portal vein drains blood from the entire gastrointestinal systems via contributions from each of the major veins.
Blood in the caval system is destined to go to what large veins?
Vena cava
What is the name for a process that results in a “back up” of blood from portal to caval circulation?
Portal hypertension
Does the body contain a numerous amount of portocaval anastomoses?
No, only a few in very specific areas.
Portocaval anatomoses connect what two structures?
It connects the portal vein to veins that flow directly into the vena cava without passing through the portal vein (caval system).
If a patient experiences damage to the liver that results in the obstruction of the portal vein, what can you expect to happen?
There will be a backup of blood into the caval systems. This is portal hypertension.
List the four portocaval anastomoses.
- Left gastric veins (portal) -> Esophageal veins (caval)
- Inferior mesenteric veins (portal) –> Rectal Veins (caval)
- Paraumbilical veins (portal) —> Superficial epigastric veins (caval)
- Colic Veins (portal) —> retroperitoneal veins (caval)
Engorgement of the esophageal veins can cause what pathology?
esophageal varices
What is the danger of the development of an esophageal varice?
Swollen veins are prone to bleeding in the esophagus.
Which is more prone to bleeding: portal esophageal varices or rectal varices?
esophageal varices
What conditions might result in the reopening of the ligamentumeres?
Hypertension of the paraumbilical vein that leads to backflow of blood into the superficial epigastric veins.
What veins radiate out of the umbilicus (belly button)?
Paraumbilical veins
Engorgement of the paraumbilical veins radiating from the umbilicus will result in what clinical finding upon abdominal examination.
Caput medusa
Engorgement of which veins could potentially cause bleeding behind the peritoneum?
Engorgement of the retroperitoneal veins
