TBL 16

Question 1

What does the parietal peritoneum line? Visceral peritoneum?

Answer 1

Parietal peritoneum lines the abdominal cavity
Visceral peritoneum invests most of the abdominal viscera.

The peritoneal cavity is the space between the two.

Question 2

What is the function of the thin peritoneal fluid film that normally occupies the peritoneal cavity?

Answer 2

The peritoneal fluid is composed of water, electrolytes and other things from the surrounding interstitial fluid. It LUBRICATES the peritoneal surfaces, enabling viscera to move over one another without friction, allowing the movements of digestion. It also contains leukocytes and antibodies that RESIST INFECTION.

Question 3

Why can peritonitis be lethal and why is the linea alba a preferred site for ascites paracentesis?

Answer 3

Peritonitis: infection and inflammation of the peritoneum. Exudation of serum, fibrin, cells and pus into the peritoneum causing pain in the overlying skin and an increase in the tone of the anterolateral abdominal muscles. Given the extent of the peritoneal surfaces and the rapid absorption of the material, including bacterial toxin, from the peritoneal cavity, when peritonitis becomes generalized, the condition is dangerous and lethal.

The linea alba avoids the inferior epigastric artery and other major nerves.

Question 4

How can peritoneal adhesions cause emergency complications?

Answer 4

limit the normal movement of the viscera

emergency complications: intestinal obstruction when the intestine becomes twisted around an adhesion

Question 5

Where do the organ primordia form during development?

Answer 5

posterior abdominal wall and protrude to varying degrees into the parietal peritoneum.

Question 6

Which organs protrude completely into the parietal peritoneum?

Answer 6

Stomach and spleen and this peritoneal investment is defined as visceral peritoneum.

Question 7

What are intraperitoneal organs?

Answer 7

They are organs invested by the visceral peritoneum.

Question 8

What are mesentries?

Answer 8

They are continuities of the visceral and parietal peritonea that result from protrusions of intra-peritoneal organs into the parietal peritoneum.

Question 9

What do the nerves that regionally innervate the abdominal wall also do?

Answer 9

They provide somatic sensory fibers to the parietal peritoneum. This way, distension or irritation of the parietal peritoneum activates the sensory fibers causing sharp, localized pain.

Question 10

What creates the lesser omentum?

Answer 10

double-layered extension of visceral peritoneum from the anterior and posterior surfaces of the proximal duodenum and stomach

Question 11

What is the greater omentum?

Answer 11

It is a prominent, four-layered peritoneal fold that hangs down like an apron from the greater curvature of the stomach and proximal part of the duodenum. After descending, it folds back and attaches to the anterior surface of the transverse colon and its mesentery.

Question 12

How does the phrenic nerve provide an exception to the concept that pressure applied to the parietal peritoneum results in sharp, localized pain?

Answer 12

Pain from the parietal peritoneum is generally well localized, except for that on the inferior surface of the central part of the diaphragm, where innervations is provided by the phrenic nerves. Irritation here is often referred to the C3-C5 dermatomes over the shoulder.

Question 13

How do functions of the greater omentum relate to its common displacement in the peritoneal cavity?

Answer 13

It is large and fat laden so it prevents the visceral peritoneum from adhering to the parietal peritoneum. It has considerable motility and moves around the peritoneal cavity with peristaltic movements of the viscera. It often forms adhesions adjacent to the an inflamed organ, walling it off and protecting other viscera from it. It is common to find it displaced from normal position.

Question 14

Where do the greater and lesser sacs lie? What connects them?

Answer 14

A surgical incision through the anterolateral abdominal wall enters the greater sac, the largest part of the peritoneal cavity.

The lesser sac (omental bursa) lies posterior to the stomach and lesser omentum.

The OMENTAL FORAMEN connects the greater and lesser sacs.

Question 15

What is the transverse mesocolon?

Answer 15

It is the mesentary of the transverse colon and it divides the greater sac into supracolic and infracolic compartments.

Question 16

What provides free communication between the infracolic and supracolic compartments?

Answer 16

left and right paracolic gutters

Question 17

How do ascites and cancer cells spread within the peritoneal cavity?

Answer 17

Paracolic gutters!

Material in the abdomen can be transported along the paracolic gutters into the pelvis, especially when the person is upright. Also, infections may extend superiorly to a subphrenic recess situated under the diaphragm, especially when a person is supine.

The paracolic gutters provide pathways fro the spread of cancer cells that have sloughed from the ulcerated surface of a tumor and entered the peritoneal cavity.

Question 18

What is the embryological derivation of the gut tube?

Answer 18

The gut tube endoderm is surrounded by visceral mesoderm.

In this way, the connective tissue and smooth muscle of the tubular wall are derivatives of the visceral mesoderm.

Question 19

What are the divisions of the gut tube?

Answer 19

cranial foregut
caudal hindgut
midgut (initially opens to the yolk sac via the vitelline duct)

Question 20

What are some derivatives of the foregut?

Answer 20

esophagus
stomach
proximal duodenum

the gallbladder, liver and pancreas endodermal buds from the proximal duodenum

Question 21

What does the midgut and hindgut form?

Answer 21

rest of the GI tract

Question 22

What are the unpaired branches of the abdominal aorta? Where do they supply?

Answer 22

celiac artery (foregut)
superior mesenteric artery (midgut)
inferior mesenteric artery (hindgut)

Question 23

Where do vitelline veins pass through en route to the sinus venosus?

Answer 23

septum transversum

Remember: after arising from the duodenum, the liver bud grows into the septum transversum

Question 24

What do the left and right vitelline veins do?

Answer 24

after draining the duodenum, the left and right vitelline veins enter the liver to form the hepatic sinusoids and hepatic veins!

Question 25

What is the derivations of the vitelline veins?

Answer 25

after formation of the left-to-right venous shunt the distal portion of the LEFT VITELLINE vein disappears

after generating the superior mesenteric vein, the enlarged RIGHT VITELLINE vein becomes the hepatic portal vein

Question 26

What is the function of the hepatic portal vein?

Answer 26

Drains venous blood from the entire GI tract and the spleen drains into the hepatic portal vein. It provides 80% blood flow to the liver.

Question 27

What is the function of the inferior esophageal sphincter?

Answer 27

Food momentarily stops here and that the sphincter mechanism is normally efficient in preventing reflux of gastric contents into the esophagus. When you are not eating, the lumen of the esophagus is normally collapsed superior to this level to prevent food or stomach juices from regurgitating into the tube.

Question 28

How does the inferior esophageal sphincter contribute to hiatal hernia formation?

Answer 28

A hiatal hernia is a protrusion of part of the stomach into the mediastinum through the esophageal hiatus of the diaphragm. It occurs because of weakening of the muscular parts of the diaphragm and widening of the esophageal hiatus.

Question 29

How is pyrosis related to GERD?

Answer 29

Pyrosis or heartburn is the most common type of esophageal discomfort. This burning sensation in the abdominal part of the esophagus is usually the result of regurgitation of small amounts of food or gastric fluid into the lower esophagus (gastroesophageal reflux disorder or GERD).

Question 30

What typically causes a congenital hernia?

Answer 30

The esophagus fails to lengthen sufficiently, and the stomach is pulled up into the esophageal hiatus through the diaphragm.

Question 31

Which artery supplies the abdominal part of the esophagus?

Answer 31

Left gastric artery from the celiac trunk

Question 32

Which vein drains blood from the abdominal part of the esophagus?

Answer 32

Left gastric vein which drains into the hepatic portal vein

Question 33

What do the tributaries of the left gastric vein anastomose with?

Answer 33

esophageal tributaries of the azygous vein, which empties into the SVC. This anastamoses creates a portal-systemic anastomosis.

Question 34

How do esophageal varices form and why are they life-threatening?

Answer 34

In portal hypertension, there is abnormally increased blood pressure in the portal venous system so blood is unable to pass through the liver via the hepatic portal vein, causing a reversal of blood flow in the esophageal tributary. The large volume of blood causes the submucosal veins to enlarge, forming esophageal varices. These distended collateral channels may rupture and cause severe hemmorage that is life threatening and difficult to control surgically.

Question 35

What is the cardiac orifice, fundus, body and pylorus of the stomach?

Answer 35

CARDIAC ORIFICE: It is the superior opening or inlet of the stomach. It usually lies posterior to the 6th left costal cartilage, 2-4cm from the median plane at the level of T11 vertebra.
FUNDUS: It is the dilated superior part of the stomach that is related to the left dome of the diaphragm.
BODY: it is the major part of the stomach between the fundus and the pyloric antrum
PYLORUS: It is the distal, sphincter region of the pyloric part. It is a marked thickening of the circular layer of smooth muscle that controls discharge of the stomach contents through the pyloric orifice into the duodenum

Question 36

What is the greater and lesser curvatures of the stomach?

Answer 36

LESSER CURVATURE: forms the shorter concave right border of the stomach.
GREATER CURVATURE: forms the longer, convex left border of the stomach.

Question 37

How does the pylorus control discharge of stomach contents into the duodenum?

Answer 37

Intermittent emptying of the stomach occurs when intragastric pressure overcomes the resistance of the pylorus. The pylorus is normally tonically contracted so that the pyloric orifice is reduced, except when emitting chyme. At irregular intervals, gastric peristalsis pushes the chyme through the pyloric canal and orifice into the small intestine for further mixing, digestion and absorption.

Question 38

Where does the common hepatic artery arise from? What does it bifurcate into?

Answer 38

The celiac trunk gives rise to the common hepatic artery which then bifurcates into the proper hepatic and gastroduodenal arteries.

Question 39

What is a branch of the proper hepatic artery that anastamoses with the left gastric artery?

Answer 39

The right gastric artery branches from the proper hepatic artery and anastomoses with the left gastric artery on the lesser curvature of the stomach.

Question 40

Where does the right gastroepiploic artery reside? what does it anastamose with?

Answer 40

The right gastroepiploic artery is a branch of the grastroduodenal artery, which resides on the greater curvature of the stomach where it anastomoses with the left gastroepiploic artery, a branch of the splenic artery.

Question 41

Which veins deliver venous blood from the stomach and spleen to the hepatic portal vein?

Answer 41

right gastric vein and the right and left gastroepiploic veins

Question 42

How do paraesophagel and sliding hiatal hernias differ?

Answer 42

There are two main types of hiatal hernias: paraesophageal and sliding hiatal hernias.

PARAESOPHAGEAL: the cardia remains in its normal position. There is a pouch of the peritoneum, often containing part of the funudus of the stomach, extends through the esophageal hiatus anterior to the esophagus. Usually no regurgitation of gastric contents occurs because the cardial orifice is in its normal position.

SLIDING: the abdominal part of the esophagus, the cardia and parts of the fundus of the stomach slide superiorly through the esophageal hiatus into the thorax, especially when the person lies down or bends over. Some regurgitation of stomach contents into the esophagus is possible because the clamping action of the right crus of the diaphragm on the inferior end of the esophagus is weak.

Question 43

How is the Helicobacter pylori infection related to gastric ulcers and why are ulcers that perforate through the posterior wall of the stomach life-threatening?

Answer 43

chronic anxiety –> increase gastric acid –> overwhelms bicarb –> reduce effectiveness of mucous lining –> increase vulnerability to H. pylori –> H. pylori erodes mucous lining, inflates mucosa making it vulnerable to effects of gastric acid and digestive enzymes –> ULCERS

A posterior gastric ulcer may erode through the stomach wall into the pancreas, resulting in referred pain to the back. Erosion of the splenic artery results in severe hemorrhage into the peritoneal cavity.

Question 44

Define the duodenum, jejunum and ileum of the small intestine.

Answer 44

DUODENUM: is the first and shortest part of the small intestine. It is also the widest and most fixed part. It takes a C-shaped course around the head pancreas.
JEJUNUM: It begins at the duodenojejunal flexure where the gastrointestinal tract resumes an intraperitoneal tract
ILEUM: ends at the union of the terminal ileum and secum.

Together the jejunum and ileum are 6-7 meters long.

Question 45

What parts of the duodenum are intraperitoneal foregut dertivatives? retroperitoneal mid-gut derivatives?

Answer 45

intraperitoneal foregut derivatives: superior part and proximal part (1) of the descending (2) part of the duodenum

retroperitoneal mid-gut derivatives: distal portion of the descending duodenum (2), the horizontal (3) and ascending (4) parts of the duodenum

Question 46

What are the spatial relationships of the 1st, 2nd and 3rd parts of duodenum?

Answer 46

1) anterior: liver and bladder posterior: gastroduodenal artery

2) anterior: transverse colon
posterior: right kidney

3) anterior: SMA (superior mesenteric artery)
posterior: aorta

Question 47

What arteries/ veins supply the duodenum?

Answer 47

Arteries: the superior pancreaticoduodenal artery, a branch of the gastroduodenal artery, and the inferiorpancreaticoduodenal artery, branch of SMA, supply the duodenum

Veins: venous blood from the duodenum drains into the hepatic portal vein

Question 48

When do duodenal ulcers cause peritonitis, which organs can become inflamed, and why can life-threatening hemorrhage occur?

Answer 48

Duodenal ulcers are inflammatory erosions of the duodenal mucosa. An ulcer may perforate the duodenal wall, permitting contents to enter the peritoneal cavity and causing peritonitis. Because the superior part of the duodenum closely relates to the liver, gallbladder, and pancreas, any of these organs may become inflamed.

Erosion of the gastroduodenal artery by a duodenal ulcer results in severe hemorrhage into the peritoneal cavity and peritonitis.

Question 49

What are the primary sites of lymph drainage from the foregut derived viscera?

Answer 49

celiac lymph nodes that surround the celiac trunk

Question 50

What nerves synapse in the prevertebral celiac ganglion?

Answer 50

The presynaptic greater splanchnic nerves (T5-T9)

Remember they pass through the corresponding segmental paraverteral ganglia of the symphathetic trunks

Question 51

What do the postsynaptic fibers from the celiac ganglion form?

Answer 51

They form the periarterial plexuses on the celiac trunk to innervate the foregut-derived viscera.

Question 52

How/ where do the visceral afferent fivers from the DRG at T5-T9 join the greater splanchnic nerves en route to the celiac ganglia?

Answer 52

The use the white communicating rami and they join the posy synaptic fibers in the periarterial plexuses

Question 53

What does the DRG at T5-T9 receive?

Answer 53

Visceral afferent fibers conveys visceral pain sensations from the foregut derivatives to the DRG at T5-T9. The DRG also receives pain sensations conveyed by the somatic sensory fibers of spinal nerves T5-T9.

Question 54

What is relayed together by the DRG at T5-T9 into the CNS?

Answer 54

SOMATIC pain, originating from the regional parietal peritoneum of the epigastric region or from cutaneous sensory fibers of the epigastric region and VISCERAL pain from the foregut derivatives are relayed together by the DRG to the CNS

Visceral pain is percieved as referred pain (dull, diffuse pain sensations felt in the epigastric region of the anterior abdominal wall). Somatic pain arising in the epigastric region is consciously perceived as sharp, localized pain.

Question 55

Why is visceral pain from the duodenal or gastric ulcers consciously perceived in the epigastric region?

Answer 55

Somatic pain from the regional parietal peritoneum of the epigastric region or cutaneous sensory fibers of the epigastric region is relayed to the together to the CNS.

Question 56

T/F: The vagus nerve contributes branches to the periarterial plexuses that supply the foregut derivatives.

Answer 56

TRUE

Question 57

What is the spleen?

Answer 57

It is the largest lymphatic organ that is positioned posteriorly in the LUQ. It is protected by the left 9th-12th ribs.

The left kidney is posteroinferior to the spleen and the splenic hilium is adjacent to the tail of the pancreas.

Question 58

Why is the spleen the most frequently injured abdominal organ?

Answer 58

The close relationship of the spleen to the ribs that normally protect it can be detrimental when there are rib fractures. Severe blows on the left side may fracture one or more of these ribs, resulting in sharp bone fragments that may lacerate the spleen.

In addition, blunt trauma to other regions of the abdomen that cause a sudden increase in intra-abdominal pressure can cause the thin fibrous capsule and overlying peritoneum of the spleen to rupture, disrupting its soft pulp.

Question 59

Which artery generates the left gastroepiploic artery?

Answer 59

Splenic artery: tortuous branch of the cliac trunk generates the left gastroepiploic artery near the splenic hilium

Near the hilium, the short gastric arteries arise from the splenic arteries to supply the fundus of the stomach.

Question 60

What is the course of veins in the spleen?

Answer 60

inferior mesenteric vein –> splenic vein (courses posterior to the pancreas) –> superior mesenteric vein –> hepatic portal vein

Question 61

What is splenomegaly and where is it palpated?

Answer 61

When the spleen is diseased, it may enlarge to 10 or more times its normal size and weight. The spleen is not normally palpable in adults. Generally if its lower edge can be detected when palpating below the left costal margin at the end of inspiration, it is enlarged to about three times its normal size.

Can happen because of granulocytic leukemia, hemolytic or granulocytic anemias

Question 62

Why are kidneys called retroperitoneal organs?

Answer 62

they do not protrude in the parietal peritoneum and only have parietal peritoneum covering their anterior surface