Gastroenterology Flashcards
What is the embryology defect in duodenal atresia?
failure to recanalize, double bubble on Xray
What is the embryological defect for jejunal/ileal atresia?
disruption of the mesenteric vessels
what is the metabolic abnormality for pyloric stenosis?
hypokalemic, hypochloremic metabolic alkalosis from vomiting HCl
How does the pancreas develop?
from the foregut. ventral buds-uncinate process and main pancreatic duct. Dorsal bud -body, tail,isthmus and accessory duct. both dorsal and ventral contribute to the head
annular pancreas-when it wraps around duodenum (abnormal rotation of ventral bud)
pancreatic divisum-when ventral and dorsal don’t fuse at 8 weeks
What type of cells are in the esophagus?
nonkeratinized stratified squamous epithelium
what are peyer patches and where are they?
ileum-lymphoid aggregates in lamina propria and submucosa
where do posterior duodenal ulcers perforate?
gastroduodenal artery leading to potential hemorrhage
Are internal hemorrhoids painful?
No-visceral innervation (above pectinate line). Below the pectinate line are external hemorrhoids- painful because somatic innervation (inferior rectal branch of the pudenal nerve)
What is Courvoisier sign?
enlarged gallbladder and painless jaundice
what is the difference between a direct and indirect inguinal hernia?
Direct-directly through parietal peritoneum (through hesselbach triangle) external inguinal ring only and medical to the inferior epigastric vessels. Lateral to rectus abominis (old)
Indirect- goes through external and internal inguinal ring because of patent processus vaginalis, follows testes into scrotum and lateral to inferior epigastric vessels (young)
what is a femoral hernia?
below inguinal ligament, through femoral canal (more common in females)
what are the borders of hesselbachs triangle?
inguinal ligament on the bottom, lateral is the inferior epigastric vessels and slope medial is rectus abdominis
What does secretin do?
decreases acid, increases bile secretion and increases bicarb so that pancreatic enz can work (inc by fatty acids in the duodenum)
What does GIP do?
glucose dependent insulinotropic peptide (glucose inhibitory peptide- decreases acid and increases insulin
what does vasoactive intestinal peptide do?
increases intestinal water and electrolyte secretion- VIPoma watery diarrhea, hypokalemia and achlorhydria
What does pepsin do and where is it secreted from?
chief cells in the stomach- digests protein
What are zymogens?
proenzymes of proteases (proteases are for protein digestion)
what are the monosaccharides and how are they absorbed?
by enterocytes- glucose, galactose and fructose, glucose and galactose are taken up by SGLT1 and fructose is taken up by facilitated diffusion through GLUT5. All tyransported to blood by GLUT2
What is the most common salivary gland tumour? whats the most common malignant tumour?
pleomorphic adenoma (chondromyxoid stroma) and epithelium (benign mixed tumour) malignant-mucoepidermoid carcinoma-mucinous and squamous components
whats a warthrin tumour
salivary gland tumour in smokers (papillary cystadeoma lymphomatosum)- benign cystic tumour with germinal centers
What is achalasia?
failure of relaxation of LES (no auerbach plexus in muscosa externa) so no postganglionic inhib neurons (no NO or VIP) so you get progressive dysphagia to liquids and solids, birds beak on X ray because dilation of esophagus then stenosis
What is the difference between HSV and CMV esophagitis?
HSV1 is punched out lesions CMV is linear lesions
What can cause pill esophagitis?
bisphosphonates, NSAIDS, tetracycline, iron and potassium chloride
Where is a Mallory Weiss tear and what is the thickness?
partial thickness mucosal tear secondary to vomiting at the GE junction
What is Plummer-Vinson syndrome?
dysphagia, iron deficiency, anemia and esophageal webs, can have glossitis, high risk of esophageal squamous cell carcinoma
What is the pathology change in Barretts esophagus?
nonkeratinized squamous cell epithelium to intestinal (nonciliated columnar cells with goblet cells)- risk of esophageal adenocarcinoma
H pylori can give you what type of lymphoma?
MALT
What is Virchows node?
L supraclavicular related to mets in stomach
What is the difference in symptoms between a gastric ulcer and duodenal ulcer?
gastric can have pain with meals, but duodenal often improves with meals
duodenal- 90% H pylori, can be inc acid or decreased mucosal protection, Zollinger-Ellison association, generally benign in terms of cancer risk, hypertrophy of brunner gland
What kind of diarrhea do you see with lactase deficiency?
osmotic with low stool ph because colonic bacteria ferment the lactose. Should have normal villi though
what happens in pancreatic insufficiency?
can’t absorb fat soluble vitamins adeK and b12
what is the microscopic morphology of crohns?
noncauseating granulomas with lymphoid appregates. Th1 mediated
What is the major difference between Zenkers diverticulum and meckels?
z= false
m-true
what is malrotation?
anomaly of midgut rotation, you get small bowel clumped on right side with ladd fibrous bands between liver and colon
What is a finding of colonic ischemia on imaging?
thumbprint sign due to mucosal edema and hemorrhage
What is Lynch syndrome?
hereditary nonpolyposis colorectal cancer (HNPCC)- AD (mutation in DNA mismatch repair genes) , can get ovarian, endometrial and skin cancers
Which marker is used for colorectal cancer monitoring, but not screening?
CEA
Which enzyme is higher in alcoholic liver disease?
AST>ALT
What is Reye syndrome?
hepatic encephalopathy in children caused by aspirin in viral infection (VZV, influenza), aspirin metabolites decrease beta oxidation of mitochondrial enz and you get hypoglycemia, steatosis SHINE-steatosis, hypoglycemina, infection, not awak (coma) and encephalopathy
What are mallory bodies?
seen in hepatic cirrhosis- intracytoplasmic inclusions of eosinophils with damaged keratin filaments
what causes nutmeg liver?
mottled appearance- budd chiari- obstruction of hepatic veins (hypercoagulable states)
what do you see in liver of alpha 1 antitrypsin deficiency?
PAS + globules
-young people with liver damage and dyspnea (inc elastase in lungs so you get decrease elastin and panacinar emphysema)
what is a gallstone ileus?
fistula between gallbladder and GI tract so you get gallstone causing GI obstruction, can see air in biliary tree (pneumobilia)
What is Charcot’s triad for acute ascending cholangitis?
jaundice, fever and RUQ pain
what are the antacids?
aluminum hydroxide
calcium carbonate
magnesium hydroxide
how does misoprostol work?
prostaglandin analog, builds up mucosal layer, decreases acid secretion
How does sulfasalazine work?
antiinflammatory and antibacterial in the colon
How does loperamide work?
agonist of u opoid receptors, slows gut motility
how does ondansetron work?
5HT3 antagonist, dec vagal stim
how does metoclopramide work?
D2 receptor antagonist, increases gut motility. Can have parkinsonian effects, tardive dyskinesia
how does orlisat work?
inhibits gastric and pancreatic lipase, can’t break down dietary fats
