Gastrointestinal Flashcards
Which portion of the small bowel contains villi or finger-like outpouchings that project into the lumen?
Duodenum
What are the crypts of Lieberkuhn and where are they located?
Simple tubular glands that rest on top of the muscular mucosae and deliver secretions to the intervillar spaces of the duodenum.
What is the function of Brunner’s glands?
To secrete alkaline mucous into ducts that track upward through the muscularis mucosae and into the crypts of lieberkuhn for release into the lumen of the duodenum.
Where are peyer’s patches located?
Lymphoid aggregates specific to the lumen.
Increased levels of what enzyme are associated with colonic adenocarcinoma?
COX-2; patients taking a COX inhibitor regularly have a lower incidence of adenomas compared to the general population.
Meckel diverticulum occurs due to a failure of what embryologic process?
Failure of obliteration of the omaphalomesenteric duct.
What are the most common presenting symptoms of intussusception?
Colicky abdominal pain and current jelly stools.
What condition is caused by the failure of ventral and dorsal pancreatic buds to fuse?
Formation of pancreas divisum, an asymptomatic condition usually only found incidentally.
What causes bleeding in Meckel diverticulum?
Ectopic gastric mucosa which produces acid and possible ulceration and bleeding.
Describe the three steps in the adenoma to carcinoma sequence.
- Progression from normal mucosa to small polyp- initial appearance of small adenomatous polyps is caused by a mutation of the APC gene on Ch. 5; 2. Increases in size of polyps- mutation of K-ras protooncogene facilitates this step. Unregulated cell growth occurs; 3. Malignant transformation of adenoma into carcinoma requires mutation of two genes p53 and DCC.
On autopsy and histology, what is characteristic of fulminant hepatitis associated with halothane use?
Atrophied and shrunken liver; histologically there is widespread centrilobular necrosis and inflammation of the portal tracts and parenchyma (appears just like fulminant viral hepatitis).
What are the clinical symptoms of inhaled-anesthetic hepatotoxicity?
Fever, anorexia, nausea, myalgias, arthralgias, rash with tender hepatomeagly and jaundice.
What lab findings are associated with fulminant hepatic necrosis due to inhaled anesthetics?
Elevated serum aminotransferases, prolonged PT, leukocytosis, and eosinophilia.
What causes prolonged prothrombin time in a patient with fulminant hepatic necrosis?
Failure of hepatic synthetic function and deficiency of factor VII.
Where does iron absorption occur?
In the duodenum and proximal jejunum.
Malabsorption of what vitamins/ minerals is common after gastrojejunostomy?
B12, folate, fat-soluble vitamins (esp. Vit. D), calcium, iron.
What effect does mu opioid analgesics have on smooth muscle cells of the sphincter of Oddi?
They contract the sphincter leading to constriction and spasm which may cause biliary colic.
Which opioid is least likely to cause contraction of the sphincter of Oddi and is indicated in biliary and pancreatic pain?
Meperidine.
What is pneumatosis intestinalis?
Air in the bowel wall which can be seen on abdominal xray as thin curvilinear areas of lucency that parallel the lumen.
In an infant with abdominal distention and bloody stool, pneumatosis intestinalis is indicative of what condition?
Necrotizing enterocolitis (NEC).
What triggers necrotizing enterocolitis in newborns?
Bacterial invasion and ischemic necrosis of the bowel wall that is associated with prematurity and initiation of enteral feeding.
What antihyperlipidemia agent causes acute gouty arthritis?
Niacin.
What are the most common adverse affects of fibrates?
Gallstones, myopathy
What are the most common adverse affects of bile acid resins?
GI upset, hypertriglyceridemia, malabsorption.