GI

Question 1

Explain gastric acid release under constitutive conditions, compared to food-related stimulus

Answer 1

source of gastric acid = H/K ATPase in parietal cells that pumps H into lumen of stomach.

His release from ECL cells binds to receptors on parietal cells, produces basal rate of acid secretion

with food stimulus, increase in rate of acid secretion either from neurocrine release of ACh (PSNS) or endocrine release of gastrin (ENS)

Question 2

protective mechanisms against gastric autodigestion

Answer 2

mucous- resists acid/enzyme action on mucose

HCO3- secreted by mucous cells, neutralizes acid

PG- bind mucous cells and parietal cells. increase production mucous, decrease acid production (inhibited by NSAIDS)

Question 3

explain pathophysiology of Peptic ulcer disease

Answer 3

dysequilibrium in stomach (increase acid or decrease mucous) = erosion stomach lining
associated with H. Pylori and NSAID use

Question 4

Treatment for ulcers and GERD (inc. MOA and SE)

Answer 4

NEUTRALIZE OR REDUCE GASTRIC ACIDITY:

1. acid neutralizing/lowering drugs
   - antacids (carbonate salts)
   - histamines H2R antagonist
   - PPI

SE: constipation, diarrhea, burping

2. H2R Antagonists- “cimetidine” reduce acid secretion (through pain pathway, but still possible via ACh/gastrin)

SE:diarrhea, headache, drowsy

3. PPIs "-prazoles"
omaprazole
inactivate H/K ATPAse
most effective
lasts 24 hr
SE: diarrhea, headache, abdominal pain, polyps

Question 5

Compare antacids, H2R, PPIs

Answer 5

PPIs: best, longest lasting

H2R; not great if there are food related cues, take at night

antacids: finite amount of acid it can neutralize, only lasts a few hours doesnt change rate of release

Question 6

treatment for ulcers only

Answer 6

=strengthen protective force

MISOPROSTAL
-PGE1 analogue
-stimulate parietal cells to reduce H release
-increase mucous production, HCO3 production
- good for NSAID induced
SE= diarrhea, cramping, abortion

SUCRALFATE
- Acid in stomach reacts, liberates components (aluminum) which bind to proteins in stomach, produce mucous gel that helps protect stomach
SE= constipation
less popular

Question 7

H. Pylori ulcer treatment

Answer 7

Reducing H+ sufficient to heal, but 80% chance of recurrence unless get rid of bacteria

so. .. Triple Therapy
- PPI, clarithomycin, amoxicillin

Question 8

constipation & cause

Answer 8

impaired bowel movements (reduced frequency)

causes: diet, stress, drug

Question 9

constipation treatments (3)

Answer 9

bulk laxatives- altered dietary intake + methylcellulose. no SE
osmotic laxatives- saline purgatives. SE = diarrhea
stimulant laxatives- se=cramp/diarrhea

Question 10

diarrhea

Answer 10

propagate indigestible residue too fast for water reabsorption to occur

cause: disease, toxins, virus, stress, anxiety, drugs

Question 11

diarrhea treatment

Answer 11

fluid & electrolyte monitoring