GI Flashcards
Most common location of salivary gland tumors:
Parotid gland
Most common salivary gland tumor:
Second most common:
Pleomorphic adenoma
Warthin’s tumor
Most common malignant salivary gland tumor:
Mucoepidermoid carcinoma
This very common genetic defect is a risk for duodenal atresia:
Trisomy 21
Jejunal, ileal, and colonic atresia are due to this event during fetal development. What about duodenal atresia?
Duodenal = failure to recanalize
Jejunal et c = vascular accident
This anterior abdominal wall defect can contain a herniated liver, whereas this does not.
Omphalocele can have the liver protruding
Gastroschisis does not
These structures are retroperitoneal (9):
A DUCK PEAR: Adrenals Duodenoum Ureters Colon (descending and ascending) Kidneys Pancreas (except tail) Esophagus Aorta / IVC Rectum
Three metabolic abnormalities that may be seen in an infant with pyloric stenosis:
Hypochloremia
Metabolic alkalosis
Hypokalemia (K+ shift into cells to allow H+ out into blood)
Pale clay colored stool, tea urine, jaundice in the first weeks of life:
Extrahepatic biliary stenosis, failure of the bile ducts to completely re-canalize.
The pancreas is derived from this embryonic structure:
Foregut
Which pancreatic bud contributes to the head and main pancreatic duct?
Ventral bud
How does an annular pancreas happen?
Ventral bud is in two pieces
Dorsal / ventral fuse abnormally and encircle the duodenum.
Where does the spleen come from? From what tissue layer is it derived?
The stomach mesentary, it’s mesodermal.
What structures come from the hepatic diverticulum off the ventral foregut?
Liver
Gall bladder / biliary tree
Ventral pancreatic bud
Which pancreatic bud travels to meet the other bud?
Ventral swings around dorsally to join the dorsal pancreatic bud.
This embryonic structure gives rise to the body, tail, and isthmus of the pancreas:
Dorsal pancreatic bud
This ligament contains the portal triad:
Hepatoduodenal
Access to the lesser sac through this ligament:
Gastrohepatic
The tail of the pancreas is embedded in this ligament:
Splenorenal
The gastric arteries are in this ligament:
Gastrohepatic
This ligament is the remnant of the fetal umbilical vein:
Ligamentum teres hepatis
What are the layers of the gut wall (inside out) (4)?
Mucosa
Submucosa
Muscularis externa
Serosa / adventitia
This type of injury extends into the submucosa:
Ulceration
Where is the myenteric nerve plexus? What is its other name?
Myenteric = Auerbach’s
It is the OUTERbach’s plexus
This nerve plexus is the inner nerve plexus and is located in the _________.
Submucosal nerve plexus is the inner one, aka Meissner’s, it’s in the submucosa, of course.
Three arteries to the GI structures come off the aorta anteriorly:
Celiac
Superior mesenteric
Inferior mesenteric
What is SMA syndrome?
The duodenum gets caught between the SMA and the aorta and is obstructed.
Parasympathetic innervation for the:
Foregut
Midgut
Hindgut
Foregut and midgut = vagus
Hindgut = pelvic
The artery that supplies the foregut:
Celiac
The three main branches off the celiac trunk:
Common hepatic
Splenic
Left gastric
The common hepatic artery gives rise to three arteries, what are they?
Gastroduodenal
Right gastric
Hepatic artery proper
This artery gives rise to the main arteries to the pancreas:
Gastroduodenal via the anterior superior pancreaticoduodenal arteries
The R gastroepiploic artery comes from this origin, and the left comes from a separate vessel:
R from the gastroduodenal (off common hepatic)
L from the splenic (off celiac trunk)
Which zone in the liver is affected first by viral hepatitis?
Zone 1 = zone closest to the portal triad
Zone III is located near what structure in the liver?
Pericentral / centrilobular veins
What direction does bile flow relative to the central hepatic vein?
Away from it, toward the triad.
This hormone causes gall-bladder contraction:
CCK
What is the most common kind of stomach hernia? The most dangerous?
Sliding hiatal = most common
Paraesophageal = most dangerous, fundus can get trapped in this one.
Where do an indirect and a direct inguinal hernia lie relative to the inferior epigastric artery?
Indirect = lateral Direct = medial
Gastrin comes from these cells:
G cells
Pro-duodenal hormone:
CCK
This hormone is anti-gastrin
These two hormones are the main off-switch for gastric acid secretion:
CCK
Secretin
Somatostatin
Where is secretin made?
S cells in the duodenum
This hormone is the anti-hormone-hormone:
Somatostatin
This hormone hits parasympathetic ganglia in the gut:
VIP = vasoactive intestinal peptide
This substance helps relax the LES:
NO
This hormone is seriously elevated in Zollinger-Ellison syndrome:
Gastrin
Three common substances that are potent stimulators of gastrin:
Calcium
Phenylalanine
Tryptophan
Three histologic / gross / lab findings in a stomach of someone with ZE syndrome:
Thick rugae
High gastrin
Glandular hyperplasia
Cells that make IF:
Parietal cells
These glands in the duodenal submucosa secrete alkaline mucus:
When might they be hypertrophied?
Brunner’s
Peptic ulcer disease
Gastrin increases acid secretion indirectly. Briefly explain how this happens:
Gastrin hits ECL cells in the gut, which release histamine; it is histamine that hits parietal cells and tells them to secrete acid.
Type of receptor on parietal cells most important for stimulating acid secretion:
H2
Two Gi coupled receptors on a parietal cell:
Prostoglandin
Somatostatin
Both inhibit acid secretion
The H2 receptor on a parietal cell works through what second messenger?
cAMP
Two hormones stimulate pancreatic secretions:
CCK
Secretin
Where are oligosaccharide hydrolases located?
At the brush border of the intestines.
What is the rate-limiting step in carbohydrate digestion?
Monosaccharide production by oligosaccharide hydrolases
This sugar transporter sends both glucose and fructose from an enterocyte into the blood:
GLUT2
Glucose and galactose enter an enterocyte on this transporter:
What kind of carrier is it?
SGLT-1
Na-dependent
How is fructose taken into an enterocyte?
Facilitated diffusion through GLUT-5
What is the plasma carrier protein for vitamin B12?
Transcobalamin
Where are each of the following vitamins absorbed? Iron, Folate, B12:
Iron: Duodenum
Folate: Jejunum
B12: Terminal ileum, needs IF
The cells in Peyer’s patches that take up antigen:
M cells
Where do B cells in the gut live?
In Peyer’s patches, inside the lamina propria
What enzyme catalyzes the rate-limiting step for bile salt formation?
Cholesterol 7a-hydroxylase
Which form of bilirubin is water-soluble – direct or indirect?
Direct = conjugated = water soluble.
Gut bacteria convert conjugated bilirubin into this molecule, which either goes out into the feces as stercobilin or gets resorbed via the mesenteric veins and sent to the kidney / liver:
Urobilinogen
This salivary gland tumor has germinal centers:
Warthin’s tumor = papillary cystadenoma lymphomatosum
This salivary tumor has mucinous and squamous parts. It is the second most common tumor overall:
Mucoepidermoid carcinoma
Most tumors in this gland are malignant:
Sublingual
What does a Warthin’s tumor look like?
A lymph node: Columnar epithelium on a wad of lymph cells with a little stroma
Loss of innervation to this plexus leads to achalasia:
Auerbach’s (myenteric)
T/F: Achalasia increases the risk of squamous cell carcinoma:
T.
Primary achalasia has a high LES opening pressure. This disorder involves a low pressure proximal to the LES:
CREST / Scleroderma
This infection can give rise to secondary achalasia:
Chagas (=Trypanosoma cruzii)
CMV esophagitis looks like:
CMV: Linear ulcers, large cells with clear perinuclear halo.
HSV esophagitis looks like:
Punched-out ulcers, large pink nuclear inclusions.
What is Whipple’s disease?
Infection with Tropheryma whipplei (gram + organism). Leads to malabsorption.
Features of Whipple’s disease (5):
WHIPped cream in a CAN: Cardiac sx Arthralgias Neurologic sx FOAMY macrophages in intestinal mucosa Lymphadenopathy
Malabsorption, neurologic manifestations, autosomal recessive, acanthocytes:
Abetalipoproteinemia
HLA associated with Celiac:
HLA-DQ2, DQ8
Three Ab you can find in Celiac disease:
Anti-endomysial
Anti-gliaden
Anti-tissue transglutaminase
Acute erosive gastritis, 3 features:
Neutrophils
Loss of surface epithelium
Purulent exudate with fibrin
Chronic gastritis, 2 features:
Lymphoid aggregates
Atrophied glands
Two injuries that can cause acute erosive gastritis:
Burns (Curling ulcer)
TBI (Cushing ulcer)
Type A gastritis: autoimmune or caused by H. pylori? Location in the stomach?
Autoimmune.
AutoAb, Anemia (pernicious), Achlorhydria
In the body of the stomach
H. pylori infection causes this type of gastritis:
Chronic, non-erosive, type B (in the antrum)
What is Menetrier’s disease?
Gastric hypertrophy with huge increase in mucous cells. Patients have protein loss sufficeint to cause hypoalbuminemia.
Super hypertrophied rugae:
Menetrier’s disease
Krukenberg’s tumor, what is it?
Bilateral metastasis of stomach cancer to ovaries. See mucus, signet ring cells.
Three places you might see signet ring cells:
Lobular adenocarcinoma in situ (breast)
Gastric cancer
Kruckeberg’s tumor of the ovary
This kind of ulcer will be accompanied by hypertrophy of Brunner’s glands:
Duodenal ulcers
What is involved in triple therapy for H. pylori?
Quadruple therapy?
PPI + clarithromycin + amox or metronidazole
PPI + bismuth + metro + tetracycline
Tx for irritable bowel syndrome (5):
Fiber TCAs SSRIs Loperamide Alosetron
Where do false diverticula commonly occur?
Most common in the sigmoid colon, where the vasa recta perforate the muscularis externa.
Three diverticula above the lower esophageal sphincter:
Zencker = above the UES Traction = mid-esophageal Epiphrenic = above the LES
Persistence of the vitelline duct, melena.
Meckel’s diverticulum
Intussusception is most common at this location:
Ileocecal junction
“Double bubble” on X-ray:
Duodenal atresia
Pneumatosis intestinalis in a premie:
Necrotizing enterocolitis
Abdominal pain out of proportion to physical findings in an elderly person:
Ischemic colitis
Most common sites for angiodysplasia (3):
Cecum, terminal ileum, ascending colon
Carcinoid syndrome, 3 associated findings:
Bronchospasm
Flushing
Diarrhea
Right sided heart disease / murmur
Most common sites for carcinoid tumors (3):
Appendix, ileum, rectum
Neurotransmitter leading to carcinoid syndrome:
5-HT
T/F: If a carcinoid tumor is confined to the GI tract, you will not see carcinoid syndrome.
T. Liver metabolizes 5-HT. Only mets outside the GI system will cause carcinoid syndrome.
Treatment for carcinoid syndrome:
Octreotide, somatostatin, find it and cut it out
This enzyme is elevated in the serum in mumps infection:
Amylase
Cause of Reye’s syndrome:
Hepatoencephalopathy 2/2 mitochondrial damage in the liver caused by aspirin + viral infection in children
Two viruses especially linked to Reye’s syndrome:
VZV, influenza B
Mallory bodies:
Alcoholic hepatitis
Does ethanol deplete ALT or AST?
ALT. This is the reason why AST > ALT in chronic alcoholic hepatitis.
What is the serum albumin ascites gradient? What does it mean to have a value >1.1?
SAAG = albumin in serum - albumin in ascites fluid. >1.1 cause is portal HTN, heart failure, Budd-Chiari.
A very common cause of GI bleeding among the elderly (excluding colon CA and diverticuar bleeds…):
Angiodysplasia
Most common cause of appendicitis in children:
In adults:
Children = lymphoid hyperplasia Adults = fecalith
Hirschprung’s disease always involves this segment of the GI tract:
Rectum
Down syndrome patients are at risk for these GI problems (4):
Duodenal atresia
Hirschprung
Celiac
Annular pancreas
Angiodysplasia is most common in the [3]:
Cecum, terminal ileum, ascending colon
Type of colon polyp with greatest malignant potential:
Villous adenoma
VILlous VILlain
This type of polyp is not a risk for CRC:
Hyperplastic
Non-malignant hamartomas, hyperpigmented lips, mouth, genitalia:
Peutz-Jeghers
Peutz-Jeghers is associated with cancer, can you name six?
CRC pancreatic small intestinal stomach breast uterine
Three big-name genes in CRC:
APC
K-RAS
p53
FAP with osseous and soft tissue tumors:
Gardner’s syndrome
FAP with a CNS tumor:
Turcot’s syndrome
TURcot’s TURban
Usually a medulloblastoma
Lynch syndrome is caused by this defect:
DNA mis-match repair
Cancer in the most proximal colon is most commonly caused by:
HNPCC = Lynch syndrome
Good marker for colon CA recurrence:
CEA
Order of gene events for CRC genesis:
APC
K-RAS
p53
AK-53
Carcinoid syndrome is caused by excess of this neurotransmitter:
5-HT
Medical treatment for carcinoid syndrome:
Octreotide / somatostatin
Tumor of neuroendocrine cells in the appendix might be likely to cause these symptoms:
Carcinoid syndrome, B-FDR: Bronchospasm (wheezing) Flushing Diarrhea R sided heart murmur
Carcinoid syndrome can be observed with a tumor in the GI tract. Explain how this happens:
Tumor must have mets to the liver. Liver otherwise metabolizes 5-HT and you do not see carcinoid syndrome from GI-confined cancers.
Inflammatory bowel disease with skip lesions and rectal sparing:
Chron’s
Inflammatory bowel disease associated with primary sclerosing cholangitis:
UC
Inflammatory bowel disease with rectal involvement:
UC
Microscopic morphology of Chron’s colon:
Of UC:
Chrons = noncaseating gramulomas, lymphoid aggregates UC = Crypt abscesses and ulcers, bleeding
Cell response mediating disease process in:
Chron’s
UC
Chron's = Th1 UC = Th2
Gross morphology of Chron’s colon (2 core features):
Cobblestoned, transmural thickening
Gross morphology of a colon in UC (3 features):
Inflammation is mucosal and sub-mucosal
Friable pseudopolyps
Loss of haustra (lead pipe appearance)
Embryonic source of tissue above the pectinate line:
Below the pectinate line:
Endoderm
Ectoderm
Painful hemorrhoids:
External hemorrhoids
Represents greatest risk for developing squamous cell CA in the anal region:
HPV 16, 18, 31
The inferior rectal artery is a branch of:
The internal pudendal
LLQ pain and bleeding:
Diverticulitis
Treatment for diverticulitis:
Metronidazole (covers anaerobes) +
TMP-SMX or Levo or Cipro
This virus is associated with intussusception:
Adenovirus
5-ASA agents (2):
These are used in treatment of?
Mesalazine
Sulfasalazine
Chron’s and UC
Most likely underlying cause of gallstones in a patient with Chron’s:
Bile acid wasting
Terminal ileum usually resorbs, damage to mucosa = less bile acid with more cholesterol = stones
Abdominal discomfort, joint pain, greasy stool, weight loss, macrophages with PAS+ granules in the lamina propria:
Whipple disease = Tropheryma whippelii
Small intestine mucosa contains PAS+ diestase-resistant granules, macrophages with rod-shaped bacilli:
Whipple disease
Red-violet, flat, macopapular lesions with hemorrhagic nodules on colonoscopy:
Kaposi’s sarcoma
Basophilic clusters on surface of intestinal mucosal cells:
Cryptosporidium
Trophozoites containing RBCs:
Entamoeba histolytica
H. pylori most highly colonizes this part of the stomach:
Antrum
Pre-pyloric area
Peri-anal fistula: More characteristic of Chron’s or UC?
Chron’s
Location of the following ulcers:
Cushing
Curling
Which are more prone to rupture?
Cushing = esophagus, stomach, or duodenum
Curling = proximal duodenum
Cushing are more prone to rupture (think increased ICP, more likely to pop)
What is the definition of an erosion?
An ulcer?
Erosion = loss of tissue that does not fully extend through the muscularis mucosa Ulcer = damage extending into the submucosa and beyond.
Chron’s disease may be linked to activity of NF-kB. What is this protein responsible for?
Chron’s = possible NOD2 defect, turns NF-kB on. NF-kB induces cytokine production.
