GI Flashcards
What molecule inhibits release of insulin and glucagon?
Somatostatin. Also inhibits pancreas, gastric secretions.
What molecule inhibits gastric acid secretion and stimulates bicarbonate secretion? Where is it made?
Secretin – S-cells duodenum
What molecule increases insulin release?
GIP - gastric inhibitory peptide
What does CCK do besides cause gallbladder contraction?
CCK inhibits gastric EMPTYING and causes pancreatic secretion. CCK is released by I cells in duodenum.
What bacterium is non-lactose fermenting and non-hydrogen sulfide forming that causes a diarrhea associated with MAHA, renal failure, and thrombocytopenia?
Shigella
What antibiotic is associated with a cholestatic, CONJUNGATED hepatitis?
Clarithomycin and other macrolides.
What type of cancer is most common in FAP?
What similar origin type of pancreatic cancer do they get?
Duodenal carcinoma!
Pancreatic carcinoma
What virus that can cause eosinophilic degeneration and condensed nuclear chromatin presents with AST»ALT, fever, joint pain, photophobia?
Yellow fever.
What kind of agent is N-acetyl cysteine and how does it work in acetaminophen toxicity?
N-acetyl cysteine is a REDUCING agent. It works by stimulating the synthesis of glutathione by reducing it. Reduced Glutathione is normally consumed by the metabolites of acetaminophen and then excreted renally. It is when these metabolites exceed the capacity of the liver to clear them that local injury ensues. It is most effective in the first 8 hrs! But can be given up to 2 days.
How does cholera activate Gs? Cholera is non-lactose fermenting and is oxidase positive. It is comma-shaped (as is campylobacter)!!!
It’s A-B toxin ADP-ribosylates the G-alpha subunit. The G-alpha unit then activates adenylyl cyclase but adenylyl cyclase cannot hydrolyze the GTP to GDP so adenylyl cyclase is constitutively activity so it makes lots of cAMP which activates protein kinase A. Protein kinase A phosphorylates CFTR increasing chlorine excretion and water efflux.
IgA is produced by plasma-differentiated B cells in the lamina propria of the small intestine. These B cells migrate there after being activated in Peyer’s patches in the lamina propria/submucosa. As such Peyer’s patches are technically not the source of IgA secretion but the site of B-cell activation that will then facilitate secretion.
Repeat
What pro-motility agent used to treat diabetic Gastroparesis can cause extra pyramidal symptoms like dystonia, Parkinsonism, and akathisia?
How does it work?
Metclopramide. It is a D2 receptor antagonist. It does nota change transit time in the colon. It increases resting tone, contractility, lower esophageal tone and motility.
What drug works by inhibiting purine synthesis and metabolism that can be used to treat refractory ulcerative colitis
Aziothioprine.
How does lactulose work?
Lactulose – when it is digested by colonic bacteria, lactulose acidifies colonic contents. This causes ammonia (NH3) to become ammonium (NH4+) which cannot cell membranes and this remains in the colon.
What valve tends to be affected in carcinoid induced cardiac valve degradation?
Tricuspid valve. Recall lung metabolizes serotonin. Serotonin in high amounts also causes bronchospasm.
