Flashcards in U-World-Gastrointestinal Deck (61)
list the four major types of non-neoplastic colonic polyps
four types of polyps= hyperplastic (well-differentiated mucosa with glands and crypts), hammartomatous (musoca, smooth muscle and connective tissue seen together), inflammatory (seen in IBD), lymphoid (often seen in children)
what kind of adenomatous polyp is carries higher risk of malignancy
(tubular adenoma has a lower associated risk)
Meckel diverticulum is a remnant of what embryologic structure?
is it a true or false diverticulum?
Meckel diverticulum= remnant of omphalomesenteric (vitelline) duct
it is a true diverticulum (contains all four layers of gut wall)
how might Meckel diverticulum cause melena/hematochezia?
Meckel diverticula often contain ectopic gastric or pancreatic tissue
==> acid secretion ==> ulceration and GI bleeding
what characteristic abnormal cell type might you see in a Kaposi's sarcoma lesion
spindle cells (elongated, stretched cells)
name the five major picornaviruses
which is acid-labile?
poliovirus, echovirus, rhinovirus, coxsackie A virus, hepatitis A virus
rhinovirus is acid-labile; therefore it cannot colonize the gut, just the respiratory tract
what are three common risk factors for gallbladder disease
"forty, fat and female"
epigastric pain following fatty meals is likely indirectly due to secretion of which hormone
in patients with biliary colic, the gallbladder is inflamed and when CCK is secreted it causes contraction of the inflamed gallbladder leading to pain
name three reducing sugars
fructose, glucose and galactose
manometric studies showing periodic non-peristaltic contractions of esophagus that are long in amplitude and duration and barium study showing "corckscrew esophagus" suggest what condition
diffuse esophageal spasm (DES)
what two main symptoms does diffuse esophageal spam cause
dysphagia and chest pain (not associated with exertion)
what immune mediator is most important in defense against Giardia lamblia
patients with what genetic disorders are at especially increased risk of chronic Giardiasis
patients with X-linked agammaglobulinemia and common variable immune deficiency
(due to deficient IgA)
what disease can inhibited inactivation of trypsin cause
trypsin acts to inactivate itself (in addition to activating itself) and when it can't do this accumulated trypsin in the pancreas leads to pancreatitis
what GI condition is diphenoxylate mainly used for and why
diphenoxylate is used to treat diarrhea;
it is an opioid and causes decreased GI motlity
in what particular location does MHC Class I bind its antigen vs. where MHC Class II binds its antigen
MHC Class I binds its antigen on the cell membrane vs.
MHC Class II which binds its antigen in the endosome
what are the two major causes of acute pancreatitis vs. less common causes
major causes: alcoholism, gallstones
less common: hypertriglyceridemia (causes cell toxicity), ERCP procedure, infection (Coxsackie, mycoplasma pneumoniae) drugs (sulfalazine, azathioprine, valproate, furosemide), structural abnormalities of the duct or ampulla, surgery, hypercalcemia
a patient from Peru with dysphagia and difficulty belching is shown to have a dilated esophagus with an area of absent peristalsis
what's the likely microbe?
(Chagas disease is associated with achalasia)
what two ligaments make up the lesser omentum
hepatoduodenal ligament and hepatogastric ligament
what kind of ulcer is associated with H. pylori infection and decreased amount of somatostatin release
(note: gastric ulcer does not require increased HCl production)
how do you differentiate between campylobacter jejuni, vibrio cholera and H. pylori (since all of them are gram negative, oxidase positive, comma-shaped rods)
campylobacter grows in 42 degrees Celcius
vibrio cholera grows in alkaline media
H. pylori produces urease
what would you see vs. not see in stool microscopy for a patient with cholera
mucus and some epithelial cells, but no leukocytes or lymphocytes because cholera doesn't invade the mucosa
what do toxin A and toxin B of C. diff do
toxin A (enterotoxin) is a chemoattractant for neutrophils
toxin B (cytotoxin) depolymerizes actin => loss of integrity of cytoskeleton
what vitamin must you supplement in patients who have had total gastrectomy
vitamin B12 (since the patient no longer has parietal cells to secrete intrinsic factor)
toxin from enterohemorrhagic E. coli is called what and acts via what mechanism?
what other toxin from what microbe acts via this same mechanism?
EHEC produces shiga-like toxin, aka verotoxin;
it degrades 28S rRNA by removing adenine and thereby inactivates the 60S ribosome
shiga-toxin from shigella has the same mechanism of action
what does 99mmTc-pertechnetate detect
99mmTc-pertechnetate detects gastric mucosa and can be used to detect ectopic gastric mucosa such as in Meckel diverticulum
what is the most common location for Crohn's disease to manifest
NK cells generally defend against what kinds of cells/pathology
NK cells defend against tumor cells or virus-infected cells
increased activity of what enzyme has been linked to recurrent adenomas of the colon