The GI System-Viscera, Blood Vessels, and Innervation

What are the two layers of the peritoneum?

1. Parietal Peritoneum
2. Visceral Peritoneum

What does the parietal peritoneum cover?

1. Abdominal and visceral walls
2. Retroperitoneal organs

What does the visceral peritoneum cover?

intraperitoneal organs

What is the function of the parietal peritoneum?

provides protection and support for the organs

How can the abdominal viscera be divided?

anatomically by their relationship to the peritoneum

What are examples of intraperitoneal organs?

1. Stomach
2. Liver
3. Jejunum
4. Spleen
5. 1st part of Duodenum
6. Transverse & Sigmoid Colon

What are intraperitoneal organs?

1. organs surrounded anteriorly and posteriorly by the visceral peritoneum
2. are connected to the posterior abdominal wall by a mesentery

What is a mesentery?

double layer of parietal and visceral peritoneum where vessels and nerves are found

What are retroperitoneal organs?

organs covered by a layer of parietal peritoneum that are immovable and difficult to dissect

Complete the SADPUCKER acronym to name all the retroperitoneal organs:

1. S-suprarenals
2. A- aorta/inferior vena cava
3. D- duodenum
4. P- pancreas
5. U- ureters
6. C- colon (ascending, descending)
7. K- Kidneys
8. E- Esophagus
9. R- Rectum

What are the divisions of the GI system?

1. Foregut
2. Midgut
3. Hindgut

* each with their own blood supply

What consists of the foregut?

last 1/3 of esophagus to first 1/2 of the duodenum

* Liver
* Biliary system
* pancreas

What consists of midgut?

second 1/2 of duodenum to middle of transverse colon

What consists of the hindgut?

second 1/2 of the transverse colon to anus

What organs are in the Right Upper Quadrant?

1. Liver
2. Stomach
3. Gallbladder
4. Duodenum
5. Right Kidney
6. Pancreas
7. Transverse Colon
8. Right Adrenal Gland
9. Small Intestine(1st part)

What organs are in the Left Upper Quadrant?

1. Liver
2. Left Adrenal Gland
3. Stomach
4. Left Kidney
5. Pancreas
6. Spleen
7. Transverse Colon
8. Small Intestine

What organs are part of Right Lower Quadrant?

1. Small Intestine
2. Large Intestine
3. Cecum
4. Appendix
5. Right Ureter
6. Right Reproductive Organs:


1. ovary
2. fallopian tube
3. spermatic cord

What organs are in the left lower quadrant?

1. Small Intestine
2. Large Intestine
3. Left Ureter
4. Left Reproductive Organs:


1. fallopian tube
2. Ovary
3. Spermatic cord
5. Sigmoid colon

What divides the quadrants of the abdomen horizontally?

transumbilical plane

What is at the intersection of all four quadrants of the abdomen?

belly button landmark

At what spinal cord level does the esophagus enter the abdomen?

Pierces the diaphragm at T10 level

What is the esophagus?

a muscular tube that:

* descends from the pharynx through the posterior mediastinum
* pierces the diaphragm
* joins the stomach

What are the three parts of the stomach?

1. Fundus
2. Body
3. Pylorus

Where are the portal triad located?

within the hepatoduodenal ligament

What is the lesser omentum?

double layer of peritoneum connecting liver to the lesser curvature of the stomach

What is the greater omentum?

2x layer of peritoneum attached to the greater curvature of the stomach, that extends uptill the transverse colon

What is the gastrosplenic ligament?

* part of the greater omentum
* connects the greater curvature of the stomach to spleen
* Contains blood vessels

How long is the small intestine?

20 feet in length

What is the diameter of the small intestine?

1-2 inches in diameter

What are the three parts of the small intestine?

1. Duodenum- 10 inches long
2. Jejunum- 8 feet long
3. Illeum- 12 feet long

What does the duodenum receive?

* receives digestive enzymes from the pancreas, bile from the liver and gallbladder

Is the first part of the duodenum retroperitoneal?

NO! but the rest of the duodenum is retroperitoneal

Most of the digestion and absorption occurs where in the GI?

jejunum

What is the shortest section of the small intestine?

duodenum

Through what, does the duodenum receive bile?

through the common bile duct

Through what, does the duodenum receive pancreatic enzymes?

through the main pancreatic duct

What are the four parts of the duodenum?

1. Superior Duodenum
2. Descending Duodenum
3. Transverse Duodenum
4. Ascending Duodenum

What is the Major Duodenal Papilla

where the pancreatic duct and common bile duct empty into the second portion of the duodenum

What are the two major attachments of the duodenum

1. Hepatoduodenal ligament
2. Suspensory Ligament of Treitz

What does the suspensory ligament of Treitz do?

holds up the duodenojejunal flexure

Where is the jejunoileum?

it’s in a space where it is bounded by the ascending colon on the right, the descending colon on the left, and transverse colon above

Where are the epiploic appendages?

in the ascending colon

Where is the Haustra?

in the bottom of the descending colon

Where is the teniae coli?

It’s near the sigmoid flexure

What are the three main external features of the colon?

1. Taeniae Coli
2. Haustrum of Colon
3. Omental appendage(epiploic appendage)

What are the teniae coli?

1. three separate longitudinal ribbons of smooth muscle
2. on the outside of ascending, transverse, descending, and sigmoid colon
3. are muscularis externa of the colon

What are the haustra?

* small pouches caused by the contraction of the teniae coli
* give colon its segmented appearance
* each haustra contracts every 25 min or so

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What are epiploic appendages?

fat-filled structures

What are the accessory structures of the digestive system?

1. Liver
2. Pancreas
3. Gallbladder
4. Spleen

What produces bile?

liver

What does bile do?

breaks down fats during digestion

What does liver do for the blood plasma?

produces certain proteins for it

What organ produces cholesterol?

liver

Liver converts ------ to ---------

glucose to glycogen

What are the clotting factors produced by the liver?

1. fibrinogen
2. prothrombin

What does the liver clear up?

drugs and other poisonous substances

What marks the left and right lobe boundary in the liver?

falciform ligament

What is the round ligament or ligamentum teres hepatis?

inferior portion of the falciform ligament that is thick and round

What was the round ligament in the fetus?

fetal umbilical vein

What is the function of fetal umbilical vein?

to bypass the liver by connecting with ductus venosus and inferior vena cava

What side of the diaphragm does the falciform ligament attach to?

the inferior side of the diaphragm & the anterior abdominal wall

Where is the falciform ligament?

on the liver’s surface

What are the two lobes of the liver on the anterior surface? Which is bigger?

right lobe and left lobe; right is bigger

What are the 2 lobes on the posterior surface of the liver?

caudate and quadrate lobe

What does the fetal umbilical vein become?

ligamentum teres or round ligament

What does ductus venosus become?

ligamentum venosum

What are the three components of the portal triad?

* portal vein
* hepatic artery
* common bile duct

Describe the flow of bile through the biliary system:

1. produced in liver
2. goes to gallbladder to be stored
3. if needed, goes to duodenum via common bile duct

What happens when there is a blockage by the gallstones?

the main pancreatic duct or biliary ducts going to the liver also get affected, in addition to the blocked ampulla of Vater

Why is it important to know the anatomy of the hepatobiliary triangle in surgery?

because there is a danger of injuring the bile duct

What are two other names for Hepatobiliary triangle?

1. Cystohepatic triangle
2. Calot’s triangle

What is the hepatobiliary triangle?

an anatomical space with the common hepatic duct medially, cystic duct laterally, and inferior border of the liver superiorly

What supplies blood to the foregut?

celiac trunk

What supplies blood to the midgut?

superior mesenteric artery

What supplies blood to the hindgut?

inferior mesenteric

What is the biggest pancreatic artery?

great pancreatic artery

What is the main arterial supply to the pancreas?

from the branches of the splenic artery that go atop the spleen to make their way to the pancreas

The pancreatic arteries are a branch of?

splenic artery

What are the three branches of the celiac trunk?

1. Left gastric artery
2. Common hepatic artery
3. Splenic artery

What are the branches of the splenic artery?

1. short gastric arteries
2. left gastroepiploic
3. pancreatic

What are the main branches of the common hepatic artery?

1. gastroduodenal
2. hepatic artery proper
3. SOMETIMES: right gastric artery

Where does the left gastric artery give off branches to?

1. cardiac portion of the stomach
2. lower end of the esophagus

53% of the time, right gastric artery is a branch of?

hepatic artery proper

What are the branches of the superior mesenteric artery?

1. inferior pancreaticoduodenal artery
2. Jejuno-ileal arteries
3. right colic artery
4. middle colic artery
5. ileocolic artery

What does the inferior pancreaticoduodenal artery supply?

the pancreas and duodenum

What does the jejuno-ileal artery supply?

the jejunum and ileum

What does the right colic artery supply?

ascending colon

What does the middle colic artery supply?

the transverse colon

What does the ileocolic artery supply?

supplies the appendix, cecum, and ilium

What is appendicular artery?

terminal branch of the ileocolic artery

What does the appendicular artery supply?

appendix

What is superior mesenteric syndrome?

When superior mesenteric artery travels over the third portion of the duodenum & compresses it

What are the branches of the inferior mesenteric artery?

1. Left Colic Artery
2. Superior Rectal Artery
3. Sigmoid arteries

What is the marginal artery of the colon AKA Drummond?

anastomoses between the inferior mesenteric and superior mesenteric arteries via the middle colic artery

Which veins drain into hepatic portal vein?

1. Splenic Vein
2. Superior Mesenteric vein & its branches
3. Inferior Mesenteric vein (INDIRECTLY DRAINS INTO IT) & its branches

Which branches of the superior mesenteric vein drains into the hepatic portal vein?

* Inferior pancreaticoduodenal vein
* right gastroepiploic vein
* veins from the jejunum and ileum
* middle colic vein
* right colic vein
* ileocolic vein

What branches of the inferior mesenteric vein indirectly drain into the hepatic portal vein?

* left colic vein
* sigmoidal veins
* superior rectal vein

What is the anastomosis that occurs between the veins of portal circulation and those of systemic circulation?

Portacaval Anastomosis

What are some important sites for the portal systemic anastomosis?

1. inferior part of the esophagus
2. inferior part of the rectum

Liver cirrhosis:

* progressive destruction of liver cells & replacement by fatty and fibrous tissue
* fatty and fibrous tissue impedes blood circulation in liver