Disposition of Peritoneum

Question 1

What is the peritoneum?

Answer 1

Continuous transparent serous membrane that lines the abdominopelvic cavity and invests the viscera.

Question 2

What is the parietal peritoneum?

Answer 2

Lines the internal surface of the abdominopelvic wall.

Question 3

What is the visceral peritoneum?

Answer 3

Covers viscera such as the stomach and the intestines

Question 4

What is the Mesentery?

Answer 4

Double layer of peritoneum that occurs as a result of the invagination of the peritoneum by an organ and constitutes a continuity of the visceral and parietal peritoneum - connects an intraperitoneal organ to body wall - usually the posterior abdominal wall

Question 5

What is the Omentum?

Answer 5

Double-layered extension or fold of peritoneum that passes from stomach and proximal part of the duodenum to adjacent organs in the abdominal cavity.

Question 6

What is the peritoneal ligament?

Answer 6

Consists of a double layer of peritoneum that connects an organ with another organ or to the abdominal wall

Question 7

What developmental processes are involved in separating the greater from the lesser peritoneal sac?

Answer 7

The lesser sac is embryologically formed from an infolding of the greater omentum.

Question 8

What peritoneal structures are derived from the ventral mesentery?

Answer 8

Liver

Question 9

What peritoneal structures are derived from the dorsal mesentery?

Answer 9

Greater omentum of the stomach, jejunum and ileum as mesentery, transverse colon as the transverse mesocolon, sigmoid colon as sigmoid mesocolon.

Question 10

What are the boundaries of the greater sac?

Answer 10

Greater sac: abdominal cavity outside of the lesser sac
Superior: diaphragm
Inferior: pelvic floor
Anterior: falciform ligament and umbilical folds

Question 11

What are the boundaries of the lesser sac?

Answer 11

Anterior: quadrate lobe of the liver, stomach, lesser omentum, gastrocolic ligament
Posterior: pancreas
Left Lateral: Left kidney and adrenal gland
Right Lateral: Omental foramen and lesser omentum

Question 12

How are the greater and lesser sacs connected?

Answer 12

Via the omental foramen (foramen of winslow or epiploic foramen) and is bounded by the portal vein, hepatic artery and the common bile duct.

Question 13

How is the parietal peritoneum innervated?

Answer 13

Served by same blood and lymphatic vasculature and same somatic nerve supply as the region of the wall it lines.

Question 14

How is the visceral peritoneum innervated?

Answer 14

Visceral peritoneum and organs it covers are served by same blood/lymphatic vasculature and visceral nerve supply.

Question 15

What abdominal organs are present in the RUQ?

Answer 15

Liver (right lobe), Gallbladder, Stomach (pylorus), Duodenum (parts 1-3), Pancreas (head), Right suprarenal gland, Right kidney, Right colic (hepatic) flexure, Ascending colon (superior part), Transverse colon (right half)

Question 16

What abdominal organs are present in the LUQ?

Answer 16

Left liver lobe, Spleen, Stomach, Jejunum and proximal ileum, left kidney, left suprarenal gland, left colic (splenic flexure), transverse colon (left half), descending colon (superior part)

Question 17

What abdominal organs are present in the RLQ?

Answer 17

Cecum, appendix, most of ileum, ascending colon (inferior part), right ovary, right uterine tube, right ureter (abdominal part), right spermatic cord (abdominal part), uterus (if enlarged), urinary bladder (if very full).

Question 18

What abdominal organs are present in the LLQ?

Answer 18

Sigmoid colon, descending colon (inferior part), left ovary, left uterine tube, left ureter (abdominal part), left spermatic cord (abdominal part), uterus (if enlarged), urinary bladder (if very full)

Question 19

What organs are supplied by the Celiac trunk?

Answer 19

FOREGUT: esophagus, stomach, liver, gallbladder, pancreas, spleen

Question 20

What organs are supplied by the Superior Mesenteric Artery?

Answer 20

MIDGUT: Jejunum, ileum, transverse colon, ascending colon, appendix, cecum.

Question 21

What organs are supplied by the Inferior Mesenteric artery?

Answer 21

HINDGUT: Descending colon, sigmoid colon, proximal rectum

Question 22

What organs are supplied by the Internal Pudendal artery?

Answer 22

Distal part of rectum and anal canal.

Question 23

What vessels are involved in the anastomoses between branches of the aorta?

Answer 23

1. Right and left gastric arteries anastomose to supply stomach
2. Right and left gastroomental (gastroepiploic) arteries anastomose to supply stomach
3. Superior and inferior pancreaticoduodenal arteries anastomose to supply the duodenum
4. Ileocolic and right arteries and right branch of middle colic artery and left colic and sigmoid arteries all anastomose with the marginal artery which supplies the colon

Question 24

What is the purpose of anastomoses?

Answer 24

Provide collateral circulation in cases of obstruction of one vessel.

Question 25

What is a Portal System?

Answer 25

Any system of blood vessels that has a capillary network at each end.

Question 26

What is the Hepatic Portal System?

Answer 26

Receives blood from the GI tract and directs it to the liver. Substances absorbed by the small intestines travel first to the liver for processing before returning to the heart and general circulation. This is called First Pass Metabolism.

Question 27

What does the Portal Vein contain?

Answer 27

Low oxygen, high nutrient blood from the GI tract and spleen.

Question 28

What are the major vessels that form the hepatic portal system?

Answer 28

Hepatic portal vein is formed from the union of the superior mesenteric and splenic veins.

Question 29

What are the major vessels that form the hepatic portal system?

Answer 29

Hepatic portal vein is formed from the union of the superior mesenteric and splenic veins.

Question 30

What additional vessel contributes to the hepatic portal system in one third of people?

Answer 30

Inferior mesenteric vein also joins superior mesenteric and splenic veins.

Question 31

What three locations are sites of potential portal-caval anastomoses?

Answer 31

1. Esophagus
2. Umbilicus
3. Rectum

Question 32

What vessels are involved in the esophageal portal-caval anastomoses?

Answer 32

Left gastric and azygous veins.

Question 33

What is the clinical significance of the esophageal portal-caval anastomoses?

Answer 33

Esophageal varices

Question 34

What vessels are involved in the umbilicus portal-caval anastomoses?

Answer 34

Paraumbilical and small epigastric veins of anterior abdominal wall

Question 35

What is the clinical significance of the umbilicus portal-caval anastomoses?

Answer 35

Caput medusae

Question 36

What vessels are involved in the rectum portal-caval anastomoses?

Answer 36

Superior rectal and middle and inferior rectal veins

Question 37

What is the clinical significance of the rectum portal-caval anastomoses?

Answer 37

Anorectal varices

Question 38

What is Portal Hypertension?

Answer 38

Increased pressure in portal venous system

Question 39

What are clinical observations seen in Portal Hypertension?

Answer 39

-Splenomegaly, ascites, abdominal pain

Question 40

How do esophageal varices and varicose veins form from Portal Hypertension?

Answer 40

Large volumes of blood flowing from portal system to systemic system at anastomoses. It can result in varicose veins. If these get really dilated they can rupture and hemorrhage –> hematemesis (if esophageal varices)