GI Facts Flashcards
1
Q
Gastrin
A
- G cells: gastric antrum, duodenal cells
- increase gastric H+ production
2
Q
Somatostatin
A
- D cells: pancreatic islets, gut mucosa
- decrease secretion of most GI hormones
3
Q
Secretin
A
- S cells: small intestine
- increase HCO3- secretion, decrease gastric H+ secretion
4
Q
CCK
A
- I cells: small intestine
- increases PANCREATIC enzymes and HCO3- secretion, causes gallbladder contraction and decreased gastric emptying esp after meal high in fat, protein
5
Q
GIP - glucose-dependent insulinoptropic peptide
A
- K cells: small intestine
- increase INSULIN release, decrease gastric H+ secretion
6
Q
Motilin
A
- M cells: small intestine
- increase GI motility
7
Q
Afotoxin induced mutation of P53 gene is associated with which organism and cancer?
A
- Aspergillus: produces toxin
- liver cancer
8
Q
Cavernous hemangioma - microscopic finding
A
blood filled vascular spaces lined by single epithelial layer
9
Q
MDs don’t LIe
A
- MEDIAL to inferior epigastric artery = DIRECT hernia
- LATERAL to inferior epigastric artery = INDIRECT hernia
10
Q
Autosomal Recessive SCID - enzyme deficiency
A
Adenosine deaminase
- enzyme functions to deaminate adenosine to inosine as an initial step to eliminate adenosine from cell
- without enzyme, adenosine accumulates in lymphocytes and is toxic —> kills T cells and B cells
11
Q
True diverticulum
A
- contains all parts of the intestinal wall: mucosa, submucosa and muscular layers
- Meckel’s diverticulum, normal appendix
12
Q
False diverticulum
A
- contains only mucosa and submucosa
- Zenker’s diverticulum, common colon ticks
13
Q
Ribavirin - MOA, use
A
Use: Treat chronic Hep C infection (with IFN-alpha and protease inhibitor)
MOA:
- RNA hypermutation —> inhibits RNA polymerase
- inhibits inosine monophosphate dehydrogenase —> depletes GTP, causes defective 5’ cap formation on mRNA
14
Q
Adenoma to carcinoma sequence for colon cancer
A
- Mutation in APC gene: progression from normal mucosa to small polyp (early adenoma)
- Mutation in KRAS gene: increase in size of polyps, signals cell proliferation ( early adenoma to late adenoma)
- Mutations in p53 and DCC: malignant transformation (later adenoma to adenocarcinoma)
15
Q
Cholestyramine - MOA
A
Bile Acid sequestrant - for high cholesterol
16
Q
Chronic mesenteric ischemia
A
- atherosclerosis of mesenteric arteries
- get diminished blood flow to intestine —> pain worse after meals because requires more blood flow
- develop food aversion to avoid pain and weight loss
17
Q
Mallory Weiss syndrome
A
- mucosal tears at the gastroesophageal junction due to severe vomiting
- common in alcoholics and bulimics
18
Q
Hep B - liver biopsy findings
A
- accumulation of HepB surface antigen within infected hepatocytes
- see finely granular, dull eosinophilic inclusions with “ground glass” appearance
19
Q
Hep C - liver biopsy findings
A
- lymphoid aggregates within the portal tracts and focal areas of macro vascular steatosis
20
Q
Gallstone ileus
A
- gallstone can cause fistula between gallbladder and the intestinal tract —> can pass through tract and get lodged in ileum (the narrowest part of the intestine)
- see gas within the biliary tree and gallbladder
- get signs/symptoms of small bowel obstruction: ab pain/distension, n/v, high pitched tinkling bowel sounds and tenderness to palpation
21
Q
What is the initiating event for appendicitis?
A
OBSTRUCTION: fecaliths most common, also hyerplastic lymphoid follicles, foreign bodies, or tumors
22
Q
Annular pancreas is caused by what?
A
Failure of migration of ventral pancreatic duct
23
Q
Riboflavin is a precursor for which coenzymes?
A
FMN and FAD
FAD participate in TCA cycle and electron transport chain (acts as a electron acceptor for succinate dehydrogenase - complex II)
24
Q
Spleen is of _____ origin but supplied by an artery from _____ origin
A
mesoderm, foregut (splenic artery off of the celiac trunk)
25
Sudan III stain
Stains stool for fat - qualitative assay to identify unabsorbed fat and test for MALABSORPTION
26
Vitamin E deficiency - clinical presentation
Predisposes cells to oxidative injury
- neuromuscular disease: ataxia, impaired proprioception, and vibratory sensation
- hemolytic anemia
27
Amanita phalloides
- poisonous mushroom
- amatoxin INHIBITS RNA POL II, halting mRNA synthesis
- amatoxin is absorbed by GI and concentrated in liver cells —> can lead to acute renal and liver failure
28
Osteogeneis imperfecta - genetic defect
mutations in COL1A1 and COL1A2 —> leads to defective type I collagen
29
Osteogenesis imperfecta - clinical features
- BONE FRAGILITY: premature osteoporosis to multiple fractures
- BLUE SCLERA (abnormally thin, can see underlying choroid)
- HEARING LOSS
- short stature, scoliosis, easy bruisibility
30
Patients who have undergone TOTAL GASTRECTOMY must receive a lifelong supplement of what?
B12 vitamin
- no more parietal cells to make IF
- do not need to replace gastric enzymes or HCl cause can still digest protein with pancreatic and intestinal proteases
31
Enteric bacteria (in gut) produce which vitamins?
Vit K, FOLATE
32
SIBO: small intestinal bacteria overgrowth
- is seen after gastric bypass surgery
- get excessive bacterial proliferation in the blind ended gastroduodenal segment (portion that gets bypassed) if food gets in there
33
IL-8
- source: macrophages and T cells
| - major effects: increased neutrophil activation and chemotaxis
34
Intestinal gastric adenocarcinoma - appearance, path findings
- solid mass that projects into stomach lumen
| - composed of glandular forming cuboidal or columnar cells
35
Diffuse gastric adenocarcinoma - appearance, path findings
- infiltrate large areas of stomach wall, grossly thickened and leathery —> LINITIS PLASTICA
- signet ring cells - mucin filled cells with peripheral nuclei
36
Oral bioavailability equation
F = (area under oral curve x IV dose)/(area under IV curve x oral dose)
37
Immune cell involved in pathogenesis of Crohns disease
Th1 cells: increase release of IL-2, INF-gamma and TNF-alpha —> NONCASEATING GRANULOMAS
38
Immune cell involved in pathogenesis of Ulcerative Colitis
Th2 cells: produce IL4, IL-5, IL6, IL-10 —> CRYPT ABSCESSES AND ULCERS
39
Polyethylene glycol - class
Osmotic laxative
40
How do osmotic laxatives work?
Pull water into intestine —> distends intestinal wall —> increases peristalsis
41
Magnesium hydroxide - class
osmotic laxative - has questionable efficacy
42
Why does pain in appendicitis shift?
- dull visceral pain at UMBILLICUS due to afferent pain fibers entering at T10 level in the spinal cord
- get more somatic pain with increased inflammation of the appendix at MCBURNEY'S POINT as it irritates the parietal peritoneum and abdominal wall
43
Most common site of intussusception
Ileocecal junction - size difference
44
Porcelain gallbladder is associated with which cancer?
Gallbladder adenocarcinoma
45
What is porcelain gallbladder?
- potential manifestation of chronic cholecystitis and multiple gallstones
- thickened gallbladder wall with rim of calcifications
46
Proton pump inhibitors inhibit which pump?
H+/K+ ATPase pump - in parietal cells, active
47
Lactase deficiency - stool labs
- increased osmotic stool gap (increased unmeasured anions)
| - decreased stool pH: bacteria ferment lactose and produces short chain fatty acids
48
Pathogenesis of alcoholic-induced hepatic steatosis
- decreased fatty acid oxidation: Main mechanism, due to excess NADH produced by alcohol dyhydrogenase and aldehyde dehydrogenase
- also impaired lipoprotein production and secretion and increased peripheral fat catabolism
49
Direct hernias
- OLDER MEN
- caused by weakness of TRANSVERSALIS FASCIA
- medial to inferior epigastric vessel
- protrude through EXTERNAL INGUINAL RING
50
Indirect hernias
- INFANTS, CHILDREN AND YOUNG ADULTS in BOTH SEXES
- caused by PATENT PROCESSUS VAGINALIS to obliterate and internal inguinal ring to close
- LATERAL to inferior epigastic vessel
- protrude through INTERNAL inguinal ring
51
Congenital pyloric stenosis - key features
- from HYPERTROPHY of pyloric sphincter —> OBSTRUCTION
- NON-BILLIOUS vomiting
- "OLIVE MASS" in right upper abdomen, epigastric region
- more in MALE infants, 2-6 weeks old
- relieve by surgical splitting of muscle
52
Side effects of Fibrates
- CHOLESTEROL STONES: inhibit cholesterol 7alpha-hydroxylase which catalyzes the rate limiting step of bile acid production —> decrease bile acid —> decrease cholesterol solubility in bile acid —> favors gallstones
- Myopathy: increased risk when taken with statins
53
Sources of BICARB in GI
- BRUNNER glands in duodenum
| - Pancreatic secretions (bicarb secreted in exchange for chloride)
54
Diagnosis of Meckel diverticulum
99mmTc-Pertechnetate scan: uptake detects ectopic gastric mucosa —> produces acid and can cause ulcers and bleeding
55
Pathyphys of Zenker diverticulum
Diminished relaxation of CRICOPHARYNGEAL muscles during swallowing —> dysphasia —> increased intraluminal oropharyngeal pressure —> herniation of pharyngeal mucosa through area of muscle weakness —> FALSE DIVERTICULUM
56
Why do you get black liver in Dubin-Johnson syndrome?
Impaired excretion of epinephrine metabolites —> histologically appear as dense pigments in lysosomes
57
CMV ulcers in ESOPHAGUS - appearance
linear, shallow ulcers
58
HSV-1 ulcers in ESOPHAGUS - appearance
punched out ulcers
59
Diarrhea, weight loss, epigastric CALCIFICATIONS in a patient with chronic alcohol use - which disease?
Chronic pancreatitis
60
Acalculous cholecystitis
- acute inflammation of the gallbladder in the absence of gallstones SECONDARY to gallbladder stasis and ischemia
- occurs in CRITICALLY ILL: sepsis, immune compromised, severe burns, trauma
61
GERD - histological findings
- basal zone hyperplasia
- ELONGATION of lamina propria papillae
- scattered eosinophils
62
Diphenoxylate - Class, MOA
- opioid anti-diarrheal agent
| - binds mu-opioid receptors and SLOWS MOTILITY
63
VIPoma - symptoms
- watery diarrhea: VIP increases intestinal chloride loss into the stool and causes sodium, water and potassium to follow
- hypokalemia
- Achlorhydria
64
Superior Mesenteric Artery Syndrome
- decreased angle between aorta and SMA
| - get obstruction of transverse duodenum because trapped between the two arteries
65
Pathway for bile acids
Produced in the LIVER —> excreted with bile —> form vesicles with micelles and are reabsorbed by TERMINAL ILEUM —> returned to liver
- increased bile acid wasting with Crohns disease —> increased risk of gallstones
66
Why is Crohns disease associated with oxalate kidney stones?
Impaired bile acid absorption in terminal ileum —> fat binds to calcium —> less calcium binds to oxalate to be excreted —> more oxalate is reabsorbed —> oxalate kidney stones
67
Most common malignant hepatic lesion is?
Metastasis from another primary site
- multiple nodules in liver —> nodules may outgrow their vascular supply and become necrotic and umbilicated
- enlarged liver
68
How to identify appendix during surgery if cannot be palpated?
Tenia coli - follow it down until all three longitudinal bands converge at base of cecum
69
Mutation in HNPCC
Mutation of DNA mismatch repair genes MSH2, MLH1 encoding for MutL and MutS
70
Which cells kills cells with decreased or absent MH1 expression or tumor cells?
NK cells
71
CREST SYNDROME
```
C = calcinosis
R = raynaud phenomenon
E = esophageal dysmotility (atrophy and fibrosis replacement of muscularis in lower esophageal —> gastric reflux symptoms)
S = sclerodactyly
T = telangiectasia
```
72
Presence of gall stones indicate _____ (increased or decreased) cholesterol, _____ bile acids and _____ phosphatidylcholine
- increased cholesterol
| - decreased bile acid and phosphatidylcholine (increase solubility of cholesterol)
73
Carcinoid tumors - microscopic appearance
Islands or sheets of uniform cells with eosinophilic cytoplasm oval-to-round stippled nuclei (tumors are derived from neuroendocrine cells)
74
Anastomoses between the IMA and SMA:
- marginal artery of Drummond: main anastomosis
| - mesenteric meandering artery (arc of Riolin)
75
Complications of Crohns
- fistulas
- abscesses
- strictures (bowel obstruction)
76
Complications of UC
- toxic megacolon
77
L sided colon cancers - characteristics
- INFILTRATE the intestinal wall
| - causes constipation symptoms of intestinal obstruction
78
R sided colon cancers - characteristics
- grow as EXOPHYTIC MASSES
- present as occult bleeding and symptoms of iron deficiency anemia
- colon cancers caused by Lynch Syndrome (HNPCC)
79
Biliary atresia
- progressive partial or complete obstruction of extra hepatic bile ducts (normal at first)
- baby is born normal, then get jaundice after first week, within first 2 months of life —> dark urine and pale stools
- elevated DIRECT bilirubin
- biopsy: intrahepatic bile duct proliferation, portal tract edema and FIBROSIS
- hepatomegaly
- txt: SURGERY
80
Lead poisoning - GI symptoms
Constipation, abdominal pain, anorexia
81
Jejunum/Ileum intestinal atresia
- due to vascular injury
- clinical findings: bilious emesis, abdominal distension
- associations: gastroschisis
82
Pigment stones
- composed of calcium salts of UNCONJUGATED bilirubin: soft, dark brown, black
- Asian ethnicity
- bacteria or helminthic infections of biliary tract —> release BETA-GLUCURONIDASE —> hydrolyzes conjugated glucuronides and increases unconjugated bilirubin
- can also be seen in hemolytic anemia —> release conjugated bili that is hydrolyzed by beta-glucuronidase
83
Diffuse esophageal spasm
- periodic, simultaneous, non-peristalic contractions of esophagus
- due to impaired inhibitory innervation within the esophageal myenteric plexus
- dysphasia to FOOD AND SOLIDS
84
Acute interstitial pancreatitis
- duct obstruction and digestion of adipose tissues by lipase
- pancreas looks edematous
- see focal areas of fat necrosis, interstitial edema and calcium deposits
85
Acute necrotic pancreatitis
- occurs if inflammatory process from acute interstitial pancreatitis continues
- ischemia damages the acinar cells —> activate trypsinogen —> auto digestion of pancreatic tissues
- see white chalky areas of fat necrosis
86
Derivatives of dorsal pancreatic bud:
- body, tail, superior aspect of the head, accessory pancreatic duct
87
Derivatives of ventral pancreatic bud:
uncinate process, inferior/posterior portion of the head, major pancreatic duct
88
Pancreas diversum
Failure of the ventral and dorsal pancreatic ducts to fuse —> pancreatic secretions are drained from two different duct systems
89
Gamma-glutamyl transpeptidase - utility as lab test
- enzyme is predominately found in hepatocytes and biliary epithelia (not found in bone)
- can be used to determine if elevated alkaline phosphatase is of bony or hepatic origin (found in both tissues)
90
Acute Hep B - liver enzymes
AST and ALT >10x normal
91
Serum sickness like syndrome in Hep B
Joint pain, lymphadenopathy, pruritic uticarial rash, RUQ pain
92
Inhaled anesthetic hepatotoxicity
- from inhaled HALOTHANE
- severe damage can lead to fulminant hepatitis that looks like viral hep infection
- labs: increased AST and ALT, increased PT time due to liver damage
93
Branches of splenic artery:
- Pancreatic
- Left gastroepiploic: strong anastomosis with R gastroepiploic
- short gastric: poor anastomoses, susceptible to ischemic injury
94
Internal hemorrhoids
- ABOVE dentate line
| - drains into middle and superior rectal veins which communicate with internal iliac and inferior mesenteric veins
95
external hemorrhoids
- BELOW dentate line
| - drains via inferior rectal vein into the internal pudendal vein which communicates with the internal iliac veins
96
Rifaximin - class, MOA
- non-absorbable antibiotic: inhibits bacterial RNA synthesis through binding of DNA dependent RNA polymerase
- decreases gut bacteria that degrade nitrogen products to produce ammonia —> DECREASES INTRALUMINAL PRODUCTION OF AMMONIA
- usually used with lactulose
97
Signs from increased estrogen in liver failure
- gynecomastia
- spider angiomata
- pubic hair loss
- testicular atrophy
- palmar erythema
98
Which medication can be taken to prevent against adenomatous polyps and the "adenoma-to-cancer" sequence?
Aspirin through COX-2 inhibition
99
Lymphatic drainage of rectum ABOVE dentate line
- inferior mesenteric and internal iliac
100
Lymphatic drainage of rectum BELOW dentate line
- inguinal nodes
101
"Bronze diabetes"
- late stage HEMOCHROMATOSIS
- triad of: skin hyper pigmentation (dark tan despite avoiding sun exposure), diabetes mellitus, and pigment cirrhosis with hepatomegaly
102
Pancreatic pseudocyst
- common complication of acute pancreatitis
- collection of fluid rich in enzymes and inflammatory debris
- walls consist of granulation tissue and fibrosis —> NO EPITHELIAL CELLS like in true cyst
103
Anal fissure
- LONGITUDINAL TEARS in mucosa from stretching (constipation, anal sex, diarrhea)
- located DISTAL to dentate line at posterior midline due to decreased blood flow in that area
104
Portal triad components
- portal vein, hepatic artery, common bile duct
| - runs through HEPATODUODENAL LIGAMENT
105
Where are dietary lipids most likely absorbed?
Jejunum (bile acids are observed in the ileum)
