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Flashcards in GI Deck (56):
1

Retroperitoneal structures

SAD PUCKER
Suprarenal (Adrenals)
Aorta and IVC
Duodenum (2nd and 3rd parts)
Pancreas (except tail)
Ureters
Colon (descending/ascending)
Kidneys
Esophagus (lower 2/3)
Rectum (lower 2/3)

2

Gastrin (source, action, regulation, notes)

- G cells (antrum of stomach)
- inc acid secretion, growth of mucosa, motility. Acts on ECL cells --> hist --> incr HCl from parietal cells
- inc secretion by stomach distension/alkalinization, amino acids (esp phenylalanine and tryptophan), peptides, vagal tone. Decr secrretion by pH <1.5
- inc in ZES and by chronic PPI use.

3

Cholecystokinin (source, action, regulation, notes)

- I cells (duodenum, jejunum)
- inc pancreatic secretion, gallbladder contraction. Dec gastric emptying. Relaxes sphincter of Oddi
- incr by fatty acids, amino acids
- CCK acts on neural muscarinic pathways to cause pancreatic secretion

4

Secretin (source, action, regulation, notes)

- S cells (duodenum)
- inc pancreatic bicarb, decrease gastric acid, inc bile secretion.
- incr secretion with acid, fatty acids in duodenum
- incr bicarb neurtralizes acids, allowing panc enzymes to fxn

5

Somatostatin (source, action, regulation, notes)

- D cells (pancreatic islets, GI mucosa)
- decrease gastric acid, pepsinogen, pancreatic/small intestin fluid secretion. Decr gallbaldder contration, decr insulin and glucagon release
- incr by acid, decr by vagal stimulation
- inhibitory and antigrowth hormone (inhibits absorption of anabolic substances.)

6

Glucose-dependent insulinotropic peptide (source, action, regulation, notes)

- K cells (duodenum, jejunum)
- Exocrine: decr gastric H+. Endocrine: incr insulin
- incr by fatty acids, amino acids, oral glucose
- AKA GIP (gastric inhibitory peptide). Oral glucose load is used more rapidly than IV due to GIP

7

Vasoactive intestinal polypeptide (VIP) (source, action, regulation, notes)

- Parasympathetic ganglia in sphincters, gallbladder, small intestine
- Incr intestinal water and electrolyte secretion, relaxation of smooth muscle and sphincters
- incr by distention and vagal stimulation. Decr by adrenal output
- VIPoma - non-alpha/beta islet cell tumor. Watery Diarrhea, Hypokalemia, Achlorhydria (WDHA sydrome)

8

Nitric oxide

- increased smooth muscle relaxation, including LES
- loss of NO is implicated in achalasia (incr tone)

9

Motilin (source, action, regulation, notes)

- Small intestine
- produces MMCs (migrating motor complexes)
- incr in fasting state
- motilin receptor agonists (e.g. erythromycin) stimulate intestinal parastalsis

10

intrinsic factor (source, action, notes)

- parietal cells (stomach)
- Binds vit B12 (required for uptake)
- autoimmune destruction of parietal cells --> chronic gastritis/pernicious anemia

11

Gastric acid (source, action, regulation, notes)

-parietal cells (stomach)
- decreased pH
- incr secretion by histamine, ACh, gastrin. Decr by somatostatin, GIP, prostaglandins, secretin
- gastrinoma: gastrin-secreting tumor that causes continuous high acid secretion and ulcers.

12

Pepsin (source, action, regulation, notes)

-Chief cells (stomach)
- decreases protein
- incr by vagal stimulation, local acid
- inactive pepsinogen is activated to pepsin by H+

13

HCO3- (source, action, regulation, notes)

- Mucosal cells (stomach, duodenum, salivary glands, pancreas) and Brunner's glands (duodenum)
- neutralizes acid
- incr by pancreatic and biliary secretion with secretin
- HCO3- is trapped in mucus that covers gastric epithelium

14

channel for absorption of glucose/galactose

SGLT1 (Na dependent)

15

fructose absorption channel

GLUT-5

16

Monosaccharide transport to blood

GLUT-2

17

Test for distinguishing GI mucosal damage from other causes of malabsorption

D-xylose test

18

rate limiting step of bile salt formation

cholesterol 7alpha hydroxylase

19

bile conjugation enzyme

UDP-glucuronosyl transferase

20

Pleomorphic ademoa

benign mixed tumor, most common salivary gland tumor. Painless, mobile. cartilage and epithelium, recurs frequently

21

Warthin's tumor

papillary cystadenoma lymphomatosum
benign cystic tumor of salivary gland with germinal centers

22

Mucoepidermoid carcinoma

malignant tumor of salivary gland. mucinous and squamous. painful mass; often involves facial nerve

23

DDx Achalasia

primary = loss of myenteric plexus
secondary = Chagas, scleroderma (CREST)

24

Whipple's dz

infxn with tropheryma whipplei (gram+).
malabsorption, cardiac, arthralgias, neuro sx. older men
path: PAS-positive foamy macrophages in intestinal lamina propria.

25

Abetalipoproteinemia

decreased synthesis of apo B --> inability to form chylomycrons --> fat accumulation in enterocytes.
Early childhood: malabsorption and neuro manifestations

26

Curling's ulcer

acute gastritis in burns (due to reduced plasma volume)

27

cushing's ulcer

acute gastritis in TBI (due to increased vagal tone --> H+)

28

Chronic gastritis types

Type A = pernicious anemia = fundus/body
Type B = H pylori = antrum

29

menetriers' dz

gastric hypertrophy with protein loss, parietal atrophy and inc mucous cells. Hypertrophied rugae. Precancerous

30

Stomach cancer (two types)

Adenocarcinoma almost always. aggressive. Acanthosis nigricans
Intestinal -- h pylori, smoked foods, achlorhydria, chronic gastritis, type A blood. Less curvature. ulcer with raised margins
Diffuse -- not h pylori. Signet ring cells. linitis plastica (grossly thickened/leathery wall)

31

Krukenberg's tumor

b/l signet ring gastric cancer mets to ovaries

32

Sister mary joseph nodules

subQ gastric mets periumbilical

33

adenomatous polyps

precancer
more villous (vs tubular) = more malignant.

34

Hyperplastic polyp

most common non-neoplastic polyp

35

Juvenile polyp

sporadic lesions in children <5. mostly rectum. If single, not malignant
Juvenile polyposis = multiple polyps , inc risk of adenocarcinoma

36

Putz-jeghers

AD syndrome with multiple hamartomas (non-malignant) throughout GIT, hyperpigmented lips, hands, genitalia. incr risk of CRC and other cancers

37

Molecular pathogenesis of CRC

2 pathways:
chromosomal instability: APC (AD mutx in FAP--involves rectum!) loss --> incr proliferation --> K-RAS mutx --> dysregulated signal transduction --> Adenoma --> p53 mutx --> carcinoma

microsatellite instability: DNA mismatch mutx: sporadic and HNPCC (proximal colon!)

38

Turcot's syndrome

FAP + malignant CNS tumor

39

Gardner's syndrome

FAP + osseous and soft tissue tumors, congenital hypertrophy of retinal pigment epithelium

40

Carcinoid tumor

Most common cancer of small bowel
path: "dense core bodies" on EM
5-HT --> wheezing, right sided murmurs, diarrhea, flushing (Sx only after mets, since liver metabolizes 5-ht).
Tx: resection, octreotide, somatostatin.

41

cavernous hemangioma

common benign liver tumor 30-50yrs. Bx contraindicated b/c of hemorrhage risk

42

hepatic adenoma

benign liver tumor 2/2 OCP or steroid use. can regress spontaneously

43

angiosarcoma

malignant liver tumor of endothelial origin. Arsenic, polyvinyl chloride

44

alpha-1-antitrypsin deficiency (inheritance, mechanism)

-codominant
- in liver: misfolded gene product accumulates in ER --> cirrhosis with PAS-positive granules)
- in lungs: lack of functioning enzyme --> decr elastic tissue --> panacinar emphysema

45

Gilbert's

mild decr in UDP-glucouronyl transferase or dec bilirubin uptake. Asymptomatic. Elevated unconjugated bili, incr with fasting and stress

46

Crigler-Najjar syndrome

Absent UDP glyucoronyl transferase.
Presents early in life.
Jaundice, kerncterus, incr unconjugated bili
Type 1: fatal. Tx plasmaphersis and phototherapy
Type 2: less severe. Responds to phenobarbital (incr liver enzyme synthesis)

47

Dubin-Johnson

Defective liver excretion --> conjugated hyperbili and black liver. benign. Rotor's is milder and no black liver

48

hemochromatosis

Sx: cirrhosis, diabetes, pigmentation, CHF, testicular atrophy, HCC
primary: AR mutx in HFE gene. HLA-A3 association
secondary: chronic transfusions
Tx: phlebotomy, deferasirox, deferoxamine

49

PBC (path, serology, association

-lymphocytic/granulomatous
- anti-mitochondrial Abs
- assoc with other autoimmune conditions

50

PSC (path, serology, association)

- onion skin fibrosis, "beading" of intra and extrahepatic ducts
-hyper-IgM
- UC

51

Acute pancreatitis (DDx, complications)

GET SMASHED -- gallstones, EtOH, trauma, steroids, mumps, autoimmune, scorpion, hypercalcemia/hyperTG, ERP, Drugs (sulfa)
- DIC, ARDS, hypocalcemia (pancreatic soap deposites), pseudocyst (lined by granulation tissue) --> rupture/hemorrhage

52

Trousseau's syndrome

migratory thrombophelbitis associated with pancreatic adeno

53

LPL deficiency

Type I
Apo C-II
elevated chylomicrons
pancreatitis, lipemia retinalis, eruptive skin xanthomas, HSM

54

LDL R deficiency

Type IIA
ApoB-100
elevated LDL
premature CAD, corneal arcus, tendon xanthoma, xanthelasma

55

ApoE deficiency

Type II
elevated chylomicrons and VLDL remnants
premature CAD/PVD
tuberoeruptive and palmar xanthoma

56

ApoA-V deficiency

Type IV
elevated VLDL
Obesity, insulin resistance, risk of pancreatitis