GI Hour #61-62
Wed, 3/5/03, 8-9AM
Mr. Roque/Wordinger
An Bui
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Pre-Exam 3 Review
Announcements: On the practical, “jejunal arteries” was the most correct answer for the intestinal
arteries. Because he emphasized that we should know vessels in correlation with their related structure, he
will throw out the question. It is not an INCORRECT answer, but it was not fair because the intestines
had been removed. He is not able to give a breakdown of practical questions because questions depend on
what structures they can find on the bodies.
Good luck on the test!
I.
II.
Exam Format-50 questions
A. 28 Physiology
B. 4 Embryology
C. 9 Anatomy
i. 2 liver, gall bladder, pancreas, spleen
ii. 2 blood vessels
iii. 2 nerve supply
iv. Portal hypertension (read Snell for clinical correlations) presented in clinical
vignette
v. Lymphatics-self-study but will not be on this test
D. 9 Histology
Anatomy-Accessory Organs
A. Surfaces of the liver (N liver surfaces)
i. Focus on H structures
1. what they represent
2. fetal homologues
3. function of fetal structures
ii. Difference between functional and classical lobes
1. Classical-falciform ligament divides liver into left and right lobe
2. Functional-IVC and gall bladder
a. Lobes named for what vessels serve it (i.e. right lobe served by
right vessels, right portal vein and artery, etc.)
b. Know components (i.e. right lobe-right lobe and caudate process
of caudate lobe)
c. EX: Which of the following structures is not drained by left
hepatic duct? (caudate process because it is part of right lobe)
iii. Ducts and sphincters involved in gall bladder
B. Different parts of Pancreas (N279)
i. Head, tail (near the hilum of the spleen), body
ii. Behind neck-origin of Superior Mesenteric artery (SMA) and vein
iii. Anterior to uncinate process-SMA and vein
iv. Anterior to head of pancreas-Gastroduodenal artery
v. Posterior to head-Portal vein
C. Spleen
i. Know structures related to spleen
ii. Anterior border-Gastric impression
iii. Posterior-Kidney
iv. Inferior-Transverse colon specifically splenic flexure
GI Hour #61-62
Wed, 3/5/03, 8-9AM
Mr. Roque/Wordinger
An Bui
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III.
v. Pancreas impression
vi. Spleen derived from dorsal mesentery (NOT FROM THE GUT)
Anatomy-Blood Supply
A. Arteries of the abdomen
i. Abdominal Aorta-3 sets of blood vessels that supply abdomen arise from Aorta
1. 2 paired (there is a right and left branch)
a. Supply urogenital tract (supply kidneys, genitals, etc.)-come off of
side of aorta
b. Posterior blood supply to abdominal wall branch from posterior
intercostals
2. 1 unpaired set arises from medial anterior part
a. Celiac-supplies foregut (structures below diaphragm)
b. SMA supplies midgut (i.e. Appendix)
c. Inferior Mesenteric artery supplies hindgut
B. Know embryological structures and adult structures derived from them!
i. Foregut, midgut, hindgut, and blood supply
ii. Junctions between structures in the adult
1. Junction of foregut and midgut- vicinity of major duodenal papilla
- other structures found here: hepatopancreatic ampulla, entry of
common bile duct
2. Junction of midgut and hindgut-distal 1/3 of transverse colon, proximal
2/3 of anal canal
iii. All accessory structures derived from foregut except spleen (supplied by Celiac
artery but NOT derived from foregut)
iv. Pancreas-derived from foregut and midgut
1. dual blood supply-Celiac and SMA
v. Do not need to know embryological rotations around the axes for test
vi. Know different structures derived from mesenteries
1. Ventral mesentery
a. Lesser omentum (hepatoduodenal and hepatogastric ligaments)
b. Falciform ligament
2. Dorsal mesentery
a. Mesentery of small intestine
b. Greater Omentum
c. Sigmoid mesocolon
vii. Ex. Questions:
1. What is the blood supply to the hepatic flexure?
–SMA (supplies midgut), major branches=right colic and middle colic
2. Splenic artery supplies which of the following structures?
--All foregut structures-Ascending colon is NOT correct (derived from
midgut)
C. Portal Vein-very important
i. Tributaries
1. Formed by union of superior mesenteric and splenic vv., posterior to the
head of the pancreas.
2. inferior mesenteric v. drains into splenic vein or directly into the portal vein
3. paraumbilical vv.-drain into the portal vein
GI Hour #61-62
Wed, 3/5/03, 8-9AM
Mr. Roque/Wordinger
An Bui
Page 3 of 5
ii. Anastomoses between branches of portal and systemic (caval) circulations:
1. Left gastric v.-azygos vv.
2. Superior rectal v.-middle rectal v. and inferior rectal v.
3. Paraumbilical vv.-ant. abdominal vv.
4. Retroperitoneal vv.-lumbar vv.
5. Veins in bare area of the liver-veins of diaphragm and internal thoracic v.
iii. Portal Hypertension
1. Be careful and make sure you know what the main manifestations are
for portal hypertension vs. the symptoms of the main problem that are
not caused by portal hypertension
2. Primary clinical manifestations
a. Enlarged veins due to back up of blood in liver
b. Increase pressure in portal vein, blood cannot go to liver, has to go
backwards
c. varicose veins (enlarged veins)
i. Occur at portal-caval anastomoses (where you have both
portal vein and vena cava tributaries)
ii. Esophagus- food erodes mucosal lining-vomiting blood
(from esophageal v.)
iii. Rectum-hemorrhoids and bleeding from the anus (from
enlarged superior rectal v.)
iv. Caput medusae around umbilicus
d. Splenic vein backup leads to splenomegaly-no anastomoses
3. Conditions causing secondary portal hypertension:
a. Problems affecting liver-cirrhosis of liver
b. Problems occurring above liver-Right heart failure leads to backup in
Inferior vena cava
c. Tumor of head of pancreas putting pressure on portal vein
d. cirrhosis of liver, jaundice and gynecomastia-caused by portal
hypertension? No!
e. These conditions cause blockage of the portal vein, but are not
manifestations due to portal hypertension
iv. With blockage of portal vein, liver is still supplied by hepatic artery
v. External iliac begins femoral v -drains leg, lower extremity
vi. Internal iliac-drains pelvis and reproductive system
1. middle rectal is a tributary
D. Nerve supply
i. Know what structures innervate the GI tract
1. Foregut
a. Thoracic splanchnic n.
b. Vagus n.
2. Midgut
a. Thoracic splanchnic n.
b. Vagus n.
3. Hindgut
a. Lumbar splanchnic (descending colonsigmoid colon)
b. Sacral splanchnic n. (rectum)
GI Hour #61-62
Wed, 3/5/03, 8-9AM
Mr. Roque/Wordinger
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c. Pelvic splanchnic n.
ii. Sympathetics
1. Derived from thoracolumbar
2. Thoracic, lumbar, and sacral splanchnic nn.
3. Preganglionic fibers synapse on the aorta
4. Postganglionic fibers continue through mesentery to viscera
iii. Parasympathetics
1. Vagus n.
2. Pelvic splanchnic n.
3. Preganglionic fibers DO NOT synapse, they pass through mesentery to
viscera
4. Distributed on viscera by Auerbach’s (myenteric) and Meissner’s
(submucosal) plexus
IV.
Histology-Intestines
A. Small intestine
i. Increase surface area (SA) for absorption
1. Plicae circulares-folds in intestinal wall
2. Villi-important for SA
a. lamina propria has lacteal for fat absorption
b. covered by simple squamous absorptive epithelium with goblet cells
c. become shorter as you approach colon-no villi in colon
3. Microvilli-finger-like invaginations off each individual columnar cell,
greatest increase in SA
ii. Glands
1. Invaginations of surface epithelium at base of villi
2. Exocrine glands punching into epithelium in area of muscularis mucosa
3. Structural features similar to gastric glands
4. Paneth Cells-make lysozymes
5. Most important: base has undifferentiated stem cells (mitotic)
a. migrate to tips of villi to replace villi cells lost
iii. Ganglion-myenteric and submucosal plexi
iv. No glands in submucosa in small intestine except:
1. Glands of Brunner in duodenum-secrete alkaline mucus
v. Some lymphatics may be present in mucosa
vi. Ileum-Peyer’s patches (diffuse lymphoid tissues that go on to form lymph
nodules)
vii. Enteroendocrine cells in intestinal glands
B. Large intestine
i. Similar to small intestine
ii. no villi
iii. Increase population of goblet cells-facilitate solid material flow
C. Appendix has large amount of lymphoid tissue
D. Anal canal
i. Keratinized stratified squamous epithelium as it merges with skin
GI Hour #61-62
Wed, 3/5/03, 8-9AM
Mr. Roque/Wordinger
An Bui
Page 5 of 5
ii. Few glands-sebaceous and circumanal glands
iii. Paneth cells in colon? –disagreement in sources, some say there are, but most say
that there are NONE present
V.
Histology-Accessory organs
A. Liver
i. Classic liver lobule (structural orientation in liver)
1. central vein-center of hexagonal shape
2. portal triads on periphery
a. artery, vein, bile duct
b. Connected by vessels all around liver
ii. Portal-Emphasize exocrine secretion (triangle)
iii. Rappaport-emphasize metabolic (diamond shape)
1. Zone 1-closest to triad
2. Zone 2
3. Zone 3-least amount of product entering liver
**Remember the 3 lobules described above are IMAGINARY ways to orient
things in the liver, not structurally how things are seen (except for classic lobule)
iv. Sinusoids
1. hepatocytes (functional cell of liver)
a. review list of hepatocyte function-endocrine/exocrine function, drug
metabolism, glycogen metabolism, glucose metabolism, synthesis of
plasma proteins
b. exocrine-bile canaliculi between hepatocyte; move in opposite
direction of blood flow
c. 3 surfaces of contact:
i. Space of Disse (endocrine)
ii. Bile canuliculi
iii. Neighboring hepatocyte
iv. Facilitates ability to diverge products of synthesis to
particular surfaces of hepatocyte
2. lined by endothelial-like cell and Kupffer cell (phagocytic abilities to get
rid of RBCs) ;
3. Ito cells hard to show but may line sinusoid
4. Space of Disse-anything secreted into blood (endocrine products) must pass
into space and pass by these cells
B. Gall bladder
i. Folds because absorptive organ to concentrate bile
ii. Tall columnar absorptive cells
iii. Lots of microvilli
iv. Lacks submucosa
C. Exocrine pancreas
i. Similar to parotid gland, major difference are centroacinar cells in pancreas
ii. Hormonal control present in pancreas, not parotid