Podcast
Questions and Answers
What enzyme is responsible for the synthesis of HCl in the stomach?
What enzyme is responsible for the synthesis of HCl in the stomach?
H+, K+-ATPase (proton pump)
How do Proton Pump Inhibitors (PPIs) accumulate in the parietal cell acid secreting spaces?
How do Proton Pump Inhibitors (PPIs) accumulate in the parietal cell acid secreting spaces?
As weak bases, they accumulate in acid compartments and are converted into reactive thiophilic sulfenamide.
What is the result of the reaction between thiophilic sulfenamide and H+,K+-ATPase enzyme?
What is the result of the reaction between thiophilic sulfenamide and H+,K+-ATPase enzyme?
Covalent bonds are formed, blocking both basal and stimulated acid formation.
What is the effect of Misoprostol (Cytotec) on gastric acid secretion?
What is the effect of Misoprostol (Cytotec) on gastric acid secretion?
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What is the therapeutic benefit of Misoprostol (Cytotec)?
What is the therapeutic benefit of Misoprostol (Cytotec)?
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What is the mechanism of action of Sucralfate (Ulsanic) in ulcer treatment?
What is the mechanism of action of Sucralfate (Ulsanic) in ulcer treatment?
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What is the effect of Bismuth subcitrate (Ulcerone) on the ulcer?
What is the effect of Bismuth subcitrate (Ulcerone) on the ulcer?
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What is a common unwanted effect of Misoprostol (Cytotec) therapy?
What is a common unwanted effect of Misoprostol (Cytotec) therapy?
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What is the contraindication for the use of Misoprostol (Cytotec)?
What is the contraindication for the use of Misoprostol (Cytotec)?
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What is the unwanted effect of Sucralfate (Ulsanic) therapy?
What is the unwanted effect of Sucralfate (Ulsanic) therapy?
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Study Notes
Gastroesophageal Reflux Disease (GORD)
- GORD results from an imbalance between defensive factors protecting the oesophagus and aggressive factors from the stomach content
- Defensive factors: antireflux barriers (LES, crural diaphragm, costal diaphragm, and the angle of His)
- Aggressive factors: gastric acidity, volume, and gastric/duodenal content
Anatomy of the Oesophagus and Lower Gastroesophageal Sphincter (LES)
- The oesophagus is a flat muscular tube that starts at the pharynx and ends at the stomach
- At the level of the diaphragm, it is surrounded by collagen and elastic fibres
- The vagus nerve supplies only parasympathetic innervation to the oesophagus, but below the neck, it carries a mixture of sympathetic and parasympathetic nerve fibres
Substances that Affect LES Pressure
- Substances that affect LES pressure include spicy foods, peppermint, chocolate, tomatoes, onions, and alcohol
- Pregnancy, smoking, and late snacks/sleeping immediately after eating heavy meals can also affect LES pressure
Treatment of GORD
- Alginic or sodium alginate suspension (Gaviscon) floats on gastric content to treat GORD
- Antacids (e.g., Mucaine, Magnesium trisilicate, and Aluminium hydroxide) and H2 blockers (e.g., Cimetidine and Ranitidine) can also be used to treat GORD
- Non-drug management of GORD includes self-directed learning and lifestyle changes
Acid Peptic Disorders
- Peptic ulcer disease (PUD) affects millions of people worldwide and has several possible causes, including NSAID use, smoking, alcohol, stress, and diet
- Clinical manifestations of PUD include abdominal pain, burning pain localized to the epigastrium, and ulcer complications such as bleeding, perforation, and pyloric stenosis
Acid Peptic Disorders - Acid Secretion
- Basal acid secretion follows a circadian rhythm, with low secretion in the morning and high secretion at night
- Cholinergic and histaminergic stimulation are the main determinants of HCl secretion
- Food ingestion is the principal physiological stimulant of HCl secretion
Acid Peptic Disorders - Mucosal Defence and Repair
- Prostaglandins, nitric oxide, mucous and bicarbonate (HCO3-), mucosal blood flow, and stabilisation of mucosal mast cells and lysosomes play a role in mucosal defence and repair
- Somatostatin plays an inhibitory role in acid secretion
Treatment of Peptic Ulcers
- Proton Pump Inhibitors (PPIs) block the activity of H+, K+-ATPase enzyme in parietal cells, thus reducing acid secretion
- Other drugs used to treat peptic ulcers include Misoprostol, Sucralfate, and Bismuth subcitrate, which promote mucosal protection and healing
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Description
This quiz covers the anatomy of the esophagus, substances affecting the lower gastroesophageal sphincter, and the management of gastroesophageal reflux disease and acid peptic disorders. It also introduces students to mucosal defence and cytoprotection.
