GI random facts Flashcards
What affects zone 2 of the liver?
Yellow fever
What affects zone 3 of the liver?
Ischemia, metabolic toxins, alcoholic hepatitis
What are the spermatic cord fascia layers and where do they come from?
Extern spermatic fascia from the external oblique, cremaster in muscle and fascia from the internal oblique, and internal spermatic fascia from the transversal is fascia
What increases gastrin secretion?
Chronic atrophic gastritis, Z-E syndrome, and chronic PPI use
What are the effects of CCK?
⬆️ pancreatic secretion, ⬆️ gallbladder contraction,⬆️ sphincter of Oddi relaxation, decrease gastric emptying
How does CCK have its effects?
Acts on neural muscarinic pathways to cause pancreatic secretion
Watery diarrhea, hypokalemia, and achlorhydria
VIPoma
Regulators of gastric parietal cell and how they work
Ach (M3) and gastrin (CCKa) activate a Gq receptors increasing IP3 and Ca. Histamine (H2) activates a Gs protein increasing cAMP. Prostaglandins/misoprostol and somatostatin activate a GI protein, inhibiting cAMP.
Where is iron absorbed?
Duodenum
Where is folate absorbed
Small bowel
Where is B12 absorbed?
Terminal ileum with bile salts, requires intrinsic factor
What catalyzes the rate limiting step in bile synthesis?
Cholesterol-7-alpha-hydroxylase
What is the body’s only mechanism of cholesterol elimination?
Bile secretion
How does bile have antimicrobial activity?
Via membrane disruption
What catalyzes the conjugation of bilirubin?
UDP-glucuronosyl-transferase
What causes achalasia?
Loss of myenteric (Auerbach) plexus
What does achalasia predispose you to?
Squamous cell carcinomA
Histopathology of esophageal squamous cell carcinoma
Solid nests of neoplasticism squamous cells with abundant eosinophilia cytoplasm and distinct borders. Areas of keratinization and the presence of intercellular bridges
Ménétrier disease
Gastric hyperplasia of mucosa causes hypertrophied rugae, excess mucus production with resultant protein loss and parietal cell atrophy with decreased acid production. Precancerous
What affects zone 1 of the liver?
Viral hepatitis
Which types of colonic polyps are non-neoplastic, neoplastic, and premalignant?
Hyperplastic and hamartomatous are non-neoplastic, adenomatous is neoplastic, and serrated is premalignant
Which type of adenomatous polyp has more malignant potential: villous or tubular?
Villous
How are serrated polyps premalignant ?
Via CpG hypermethylation phenotype pathway with microsatellite instability and mutations in BRAF
“Saw tooth” pattern of crypts
Serrated polyp
FAP
AD, mutation of APC on chromosome 5q
Gardner syndrome
FAP plus osseous and soft tissue tumors, congenital hyper trophy of retinal pigment epithelium, impacted/supernumerary teeth
Turcot syndrome
FAP plus malignant CNS tumor
Peutz-Jeghers syndrome
AD, numerous hamartomatous polyps plus hyperpigmentation, increased risk of colorectal, breast, stomach, small bowel, and pancreatic cancer.
Pigmented mucocutaneous Macules on the buccal mucosa
Peutz-Jeghers syndrome
What is fetor hepaticus?
Musty smelling breath from liver cell failure/cirrhosis
When can you see elevated amylase
Acute pancreatitis/mumps
Mechanism of Reye syndrome
Aspirin metabolites decrease beta-oxidation by reversible inhibition of mitochondrial enzymes
Risk factors for angiosarcoma of the liver
Arsenic and vinyl chloride
Cirrhosis with PAS positive granules in liver
Alpha-1-antitrypsin deficiency
Treatment for Crigler-Najjar syndrome
Not good, but plasmapheresis and phototherapy. Type II responds to phenobarbital, which increases liver enzyme synthesis
How is copper normally excreted?
Into bile by hepatocyte copper transporting ATPase (ATP8B gene)
Pathology of primary biliary cirrhosis
Autoimmune reaction so lymphocytic infiltrate and granulomas causing destruction of intralobular bile ducts
Antibody in PBC
Anti-mitochondrial antibody, including IgM
Pathology of PSC
Concentric onion skin bile duct fibrosis, alternating structures and dilation with “beading” of intra and extra hepatic bile ducts on ERCP, MRCP
Where does pancreatic adenocarcinoma come from
Arises from pancreatic dicta (disorganized glandular structure with cellular infiltration)
When do you take H2 blockers
Before you dine. Think “table for two”
Which h2 blocker is a cyp450 inhibitor
Cimetidine, it also has anti-androgens can effects and can cross bbb causing confusion, dizziness, headaches. Can also cross the placenta
MOA of misoprostol
A PGE1 analog. Increases production and secretion of gastric mucous barrier, decreases acid production. Also used off label for induction of labor (ripens the cervix)
Side effects of aluminum hydroxide
Constipation and hypophosphotemia, proximal muscle weakness, osteodystrophy, seizures
Side effects of calcium carbonate
Hypercalcemia, rebound acid increase, can chelate and decrease the effectiveness of other drugs (eg, tetracycline)
Side effects of magnesium hydroxide
Diarrhea, hyporeflexia, hypotension, cardiac arrest
How does lactulose work for hepatic encephalopathy?
Gut flora degrade it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4
MOA of ondansetron
5HT3 antagonist
MOA of metoclopramide
D2 receptor antagonist
