GI Tract and Associated Organs
1. Describe the relationship between the diaphragm and the esophagus.
The esophagus passes through the diaphragm at the right crus. The right crus comes off the diaphragm to form
the esophageal hiatus, when they contract they squeeze on the esophagus. This constriction prevents stomach
acid from going up through the z-line of the esophagus. The epithelium of the digestive tract changes from a
moist mucosa at the esophagus to stomach epithelium at the stomach, the mucosa of the epithelium can’t
handle stomach acid. The vagal trunk nerves also pass through the diaphragm at the same point as the
esophagus does. There is a ligament, the phrenicoesophageal ligament, that holds the esophagus in the
diaphragm, these fibers run both superiorly and inferiorly to the esophagus.
2. Name and describe labeled structures
A
B
C
D
A- Diaphragm- Acts as a esophageal sphincter
B- Upper limb of phrenicoesophageal ligament- Holds the esophagus to the diaphragm
C- Lower limb of phrenicoesophageal ligament- holds esophagus in place
D- Esophagogastric junction (z-line)- Transition point between esophagus and stomach.
3. What is a hiatal hernia? What symptom does it lead to?
Occurs when a part of the stomach protrudes through the diaphragm. It can be caused by a developmental
defect or, more commonly, a loosening of the phrenicoesophageal ligaments. Loosening of the ligaments
destroys the sphincter and can lead to stomach acid crossing the z line entering the mucosa of the esophagus,
this is called pyrosis. Pyrosis that occurs more than once per week can lead to GERD or Gastroesophageal Reflux
Disease.
4. Name and describe each structure
I
J
K
A
B
C
L
H
E
D
F
G
A- Cardiac region- First part of the stomach
B- Lesser curvature- the lesser omentum attaches to this
C- Angular incisures- Stomach changes confirmation from vertical to horizontal
D- Duodenum-first part of the small intestine
E- Pyloric canal- Lumen narrows here as you go towards pyloris
F- Pyloric antrum- First part of pyloric portion of stomach
G- Body- largest part of stomach
H- Greater curvature- The greater omentum attaches to this part of the stomach
I-
Fundus- Top part of stomach, after cardiac region, gas ends up at this part of the stomach
J-
Cardiac notch
K- Abdominal esophagus- Normally much shorter and not visible because it occurs immediately after the
diaphragm.
L- Pyloris- Indistinct on outside of stomach, continued narrowing of the pyloric part.
5. Name and describe each structure
A
B
C
D
F
E
A- Cardiac orifice- Change in smooth muscle fibers occurs here
B- Gastric Folds (Ruggae) Folds in smooth muscle of stomach that run inferiorly
C- Gastric canal- Spaces in between the folds of the smooth muscle wall
D- Pyloric orifice- opening in the pylorus that allows food to leave the stomach
E- Pyloric sphincter- smooth muscle at the end of the stomach that closes or opens to allow gastric juices to
pass
F- Pylorus- Entire ending of the stomach, includes spincter and orifice
6. Name and describe each structure
A
B
C
A- Pyloric sphincter- Last place where food has to pass through
B- Pyloric canal- Narrowing of the stomach
C- Pyloric antrum- First part of pyloric region.
7. For further review of GI blood supply see #19 on the previous notes
8. Where do you find most of the arteries associated with the stomach?
Found along the border of the stomach.
9. Describe the venous drainage of the stomach.
The veins are located in the same places as the arteries, all of the veins drain into the portal vein and into the
liver.
10. Name and describe each of the following structures.
A
J
C
I
H
B
G
D
E
ABCDEFGHI-
F
Superior part- first part, it interacts with the pyloris
Descending part- Bile and enzymes from pancreas added here
Plicae circularis- ridges in SI that increase absorption
Minor duodenal papilla- Pancreatic enzymes enter here. Sodium bicarb (to neutralize stomach acid)
enters here as well
Major duodenal papilla -Bile salts and pancreatic enzymes enter here. Sodium bicarb (to neutralize
stomach acid) enters here as well
Inferior part- The superior mesenteric artery and vein pass anterior to this, the aorta and IVC pass
posterior.
Ascending part- Transition to jejunum occurs here
Duodenal flexure- where duodenum becomes jejunum
Suspensatory ligament of duodenum (ligament of Treitz)- Ligament that acts on duodenal flexure, when
contracted, it will decrease the angle between the duodenum and jejunum to permit better flow.
11. Name and describe the following structures.
A
B
C
D
H
E
G
F
ABCDEFGH-
Gastroduodenal artery
Superior pancreatoduodenal artery
Posterior superior pancreatoduodenal artery
Anterior superior pancreatoduodenal artery
Posterior Inferior pancreatoduodenal artery
Anterior inferior pancreatoduodenal artery
Superior mesenteric artery
Inferior pancreatoduodenal artery
12. Describe Arteriomesenteric occlusion of the duodenum.
This disease occurs in tall people that have weak abdominal muscles. It occurs because when gravity pulls down
on the superior mesenteric artery it can crush the duodenum at the third (inferior) part, causing this part to be
occluded. Once this is occluded, it will lead to vomiting 1-2 hours after meals (because when food cannot go
through the GI tract, it will reverse).
13. What are duodenal ulcers?
Ulcers are wearing away of a part of the GI tract. A lot of ulcers occur in the superior part of the duodenum, near
the stomach.
14. What are the differences between the Jejunum an Ileum in terms of Diameter, thickness of the wall, blood
vessel composition, amount (and location)O of fat, plicae, appearance of walls?
Feature
Jejunum
Ileum
Diameter
Same
Same
Wall
Thicker
Thinner
Vessels
Fewer arcades, longer vasa recta,
More arcades, shorter vasa recta,
poorer anastamoses
better anastamoses
Amount of fat
Less, located in mesentery
More, fat wraps around sides
Plicae
More
Fewer
Appearance of walls
Feather-like, because of more plicae
Darker because fewer plicae
15. Name and identify
B
A
D
C
A- Jejunum
B- Ileum
C- Arcades
D- Vasa Recta
16. What is an intusseception?
This occurs when part of the intestinal wall folds in on itself so that it may occlude the pathway of food through
the small intestine. If the blood supply to a particular wall was also compromised, it can lead to necrosis.
17. What is a volvulus?
This is a twisting of a loop to such an extent that it constricts blood flow through the mesentery, a loop forms in
the intestine so that the intestine will twist blood vessels within the mesentery.
18. Name and identify.
G
H
F
I
B
A
E
C
D
L
J
K
A- Teniae coli- Smooth muscle that lines the entire colon
B- Omentum appendices- fat loblues that lies the teniae coli
C- Haustra- They are folds on the colon wall that line the wall.
D- Semilunar fold- They are the folds formed by the haustra
E- Ascending colon- Colon continuous with the appendix, contains the cecum or opening to the colon
F- Right colon flexure- to the transverse colon
G- Transverse colon- the “straight part of the colon, superior most part
H- Left colon flexure- Between transverse and descending colon
I-
Sigmoid colon
J-
Rectum and anal canal
19. What is a possible function of the appendix? Where is the appendix located? What causes appendicitis
It has a lot of lymphoid tissue and therefore could act in the immune response. The appendix is located at the
posterior part of the ascending colon. In most people it is located behind the cecum, but sometimes it is located
towards the pelvis. Appendicitis is caused when fecal material is lodged in the appendix.
20. What is diverticulitis? Diverticulosis?
Diverticulitis is inflammation of the diverticulum, diverticulosis is the presence of diverticula in the large
intestine.
21. Name and label.
B
A
C
D
H
E
F
G
ABCDEFGH-
Right Lobe
Coronary Ligament
Left triangle ligament
Left lobe
Falciform ligament
Round ligament of liver (Ligament teres)
Gallbladder
Cantlie line- From the IVC to the notch of the gallbladder. Represents the physiological barrier from the right
to left lobes.
22. Describe the blood flow through the liver.
Blood can enter the liver via the portal vein or the hepatic artery. The portal vein provides blood from the GI
tract that will leave via the hepatic veins. The hepatic artery provides oxygenated blood to supply the liver with
nutrients.
23. What does segmental blood supply refer to?
It refers to fact that there are 8 “segments” within the liver, therefore one segment of the liver can be removed
but the rest of the liver can survive.
24. What is the relationship between the triangular ligaments and the coronary ligament?
The triangular ligament is 2 layers stuck together, when they split apart, it is now the coronary ligament.
25. Label and describe.
G
H
I
J
K
B
F
L
A
E
C
D
ABCDEFGHIJKL-
Left lobe of liver
Left triangular ligament
Porta hepatis- contains vessels going into liver
Quadrate lobe
Ligament of teres- old umbilical vein
Ligamentum venosum
Anterior coronary ligament
Posterior coronary ligament
Falciform ligament
Caudate lobe
Bare area
Right lobe
Name the anatomical and functional lobes:
Anatomical: left, right caudate and quadrate
Functional-left, right caudate
26. Name and identify
D
A
E
B
F
C
G
H
I
A-Fundus
B- Body
C-Neck-Contains valve that helps control bile concentration in gall bladder or in duodenum.
D- Right and left hepatic duct
EFGHI-
Cystic Duct
Common Bile duct- Travels behind the duodenum
Accessory pancreatic duct-pancreatic enzymes go through here
Main pancreatic duct
Hepatoapancreatic ampulla-Place where bile duct and pancreatic duct enter the duodenum.
27. Name and identify
A
D
C
E
G
B
F
ABCDEFG-
Sphincter of bile duct
Major duodenal papilla- Underneath the hepatopancreatic ampulla, this sits to protect the lumen of ampulla.
Descending duodenum
Bile Duct
Pancreatic Duct
Hepatopancreatic ampulla
Sphincter of pancreatic duct
28. How does the bile duct work when there is food or no food?
If there is no food, the b ile duct is closed and bile goes into the gall bladder, if there is food, bile goes into the
bile duct and/or into the lumen of the duodenum
29. How are gallstones formed? How do they affect the body?
In older peple, if too much water is removed from their bile, the salt will precipitate out and form stones,
sometimes these stones can get stuck in various spots and bile cannot get into the duodenum. Backed up bile is
called cholecystitis, in this the gallbladder becomes enlarged and infection develops. Cholelythysis is the
presence of stones
1. What are the functions of the pancreas? Where is it located?
Endocrine- release enzymes involved in carbohydrate digestion (insulin/glucagon)
Exocrine- Release sodium bicarbonate and pancreatic enzymes
The pancreas is located in the posterior aspect of the abdomen
2. What are the pathways of the major pancreatic ducts?
The main pancreatic duct goes through the entire tail, body, neck region and enters the duodenum at the major
duodenal papilla along with the bile duct
The accessory pancreatic duct loops around the main pancreatic duct and enters the duodenum at the minor
duodenal papilla
3. Label and identify
K
B
C
I
D
E
F
G
A- Main Pancreatic Duct
B- Right Hepatic duct
C- Left hepatic duct
J
A
H
DEFGH-
Common hepatic duct
Cystic duct
Accessory pancreatic duct
Major duodenal papilla
Head- located in the pocket of the duodenum
a. Uncinate Process- comes off the head and is located posterior to the superior mesenteric artery
I- Body
J- Neck
K- Tail- Goes up to the hilum of the spleen
4. Label the blood vessels
A
C
B
D
E
F
G
K
H
J
I
ABCDEFGHIJK-
Short gastric arteries
Celiac trunk
Common hepatic artery
Gastroduodenal artery
Superior pancreaticoduodenal artery
Posterior superior pancreaticoduodenal artery
Anterior superior pancreaticoduodenal artery
Posterior inferior pancreaticoduodenal artery
Anterior inferior pancreaticoduodenal artery
Superior mesenteric artery
Inferior pancreaticoduodenal artery
5. What is the function of the spleen?
The spleen functions to filter out red blood cells and screen for foreign materials
6. Describe the structure of the spleen.
The spleen is a delicate organ that has a capsule underneath the visceral peritoneum. If the spleen is damaged
or ruptured, blood can collect in this thin capsule, producing a splenic hemorrhage. If the spleen then ruptures it
can lead to massive abdominal bleeding.
7. What is the flow of blood after a spleen has ruptured?
After the spleen has ruptured, it bleeds into the supracolic portion of the greater sac. Then blood will flow into
the hepatorenal pouch, enter the right paracolic gutter and to the pelvis.
8. What are the symptoms of a ruptured spleen?
Abdominal pain-because blood will irritate the parietal peritoneum. Rigidity of the abdomen because muscles
tighten in this area. Pneumothorax-since the costodiaphragmatic recess is in this area, air can get into the space
within the lungs and cause a pneumothorax.
9. Label the diagram
D
A
B
C
A-spleen
B- visceral peritoneum
C- Splenorenal ligament
D-Gastrosplenic ligament