List and explain the 4 defensive factors which protect the stomach and duodenum from self-digestion. Mucus - forms a barrier to protect underlying cells from gastric acid and pepsin. Bicarbonate - neutralizes any acid which penetrates the mucus. Blood flow - maintains integrity or health of the muc...
NUR 311 Exam 2 Questions and
Complete Answers
List and explain the 4 defensive factors which protect the stomach and duodenum from
self-digestion. ✅Mucus - forms a barrier to protect underlying cells from gastric acid
and pepsin.
Bicarbonate - neutralizes any acid which penetrates the mucus.
Blood flow - maintains integrity or health of the mucosa
Prostaglandins - Stimulates mucus and bicarbonate, vasodilates blood vessels,
suppresses gastric secretion
List and explain 5 aggressive factors which predispose the stomach and duodenum to
ulcerations. ✅Helicobacter pylori (H. Pylori) - gram-negative bacillus which lives
between the mucus layer and the mucosa. Produces CO2 and ammonia from urea
which damages the mucosa.
Nsaids - decreases the production of prostaglandins which decreases blood flow,
decreases bicarbonate and mucus secretion, and increases gastric acid.
Gastric Acid - injures cells of the mucosa and activates pepsin.
Pepsin - breaks down protein of the gut wall.
Smoking - delays healing of ulcers and increases risk of recurrence.
What are three mechanisms of action for antacids? ✅Binds gastric acid and forms a
neutral salt, decreases pepsin if ph > 5, and stimulates prostaglandins.
How are antacids administered in relation to meals, sleep, or other drugs? If not eating,
how often are they given? ✅1 and 3 hrs after meals and at bedtime, 1 hour before
another drug, or every 2 hours if not eating
Which antacids can cause complications in heart failure and renal disease?
✅Aluminum hydroxide and sodium bicarbonate - heart failure, magnesium hydroxide -
CNS toxicity in renal patients
How do histamine2 receptor antagonists work? ✅Block H2 receptors on parietal cells
which suppress gastric acid secretion and decrease the hydrogen ion concentration in
gastric acid.
How are histamine2 receptor antagonists administered in relation to meals? ✅May be
taken without regard to meals, except take Tagamet with food
Which histamine2 receptor antagonist is noted for drug-drug interactions caused by
inhibition of hepatic drug-metabolizing enzymes? ✅cimetidine (Tagamet)
, Which histamine2 receptor antagonist is known for its ability to block androgen effects?
✅cimetidine (Tagamet)
Proton-pump inhibitors may decrease the absorption of antifungals by what action?
✅Decreased gastric acid production
When are proton pump inhibitors given? ✅Esomeprazole (Nexium) is given one hour
before a meal. Omeprazole (Prilosec) and lansoprazole (Prevacid) are given directly
before a meal. Others may be given at any time.
How long does it take for full recovery of the H+, K+-atpase pump after stopping a
proton pump inhibitor?
Why? How long for partial recovery? ✅Weeks due to irreversible inhibition. 3-5 days.
Why is misoprostol (Cytotec) used?
What are the mechanisms of action? ✅Prevention of NSAID-caused gastric ulcers.
Stimulates the secretion of mucus and bicarbonate, vasodilates blood vessels, suppress
gastric acid secretion. Replaces prostaglandins.
Why is misoprostol (Cytotec) not given during pregnancy? ✅Stimulates uterine
contractions.
How does sucralfate (Carafate) work? When should it be given? ✅Polymerization and
cross-linking occurs when the ph is < 4. It adheres to the crater for 6 hours. Given on an
empty stomach.
How many hours must elapse between an antacid and sucralfate (Carafate)? Between
other drugs and sucralfate (Carafate)? ✅1 hour between an antacid and sucralfate.
2 hours between drugs and sucralfate.
In order to kill Helicobacter pylori, what combination of drugs is given? ✅2-3 antibiotics
with a proton pump inhibitor or histamine-2 receptor antagonist
How does bismuth (Pepto-Bismol) work? What are two common side effects?
✅Disrupts the cell wall of H. Pylori, inhibits urease, and keeps H. Pylori from adhering
to the mucosa. Black tongue and stools.
At what ph will pepsin be decreased? ✅> ph 5
What is the preferred drug category for the prevention of NSAID-induced ulcers?
✅Proton Pump Inhibitors
What are two signs of gastrointestinal bleeding? ✅Black, tarry stools and coffee-
ground vomitus.
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