Physiology · Gastrointestinal System

Physiology of peptic ulcer disease

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Definition

  • Peptic ulcer disease (acid-peptic disease) is ulceration of the gastric or duodenal mucosa by acid and pepsin, from decreased mucosal defense, acid hypersecretion, or infection.
  • Ulcers occur far more often in the duodenum than in the stomach.

Diminished Mucosal Barrier

  • Mucosal defense is provided by a mucus gel layer: mucin, phospholipid, electrolytes (mainly HCO3−) and water.
  • It separates bicarbonate-rich epithelial secretion from acidic gastric content, keeping epithelial pH alkaline.

Mucus gel layerabout 0.2 mm thick

  • Acid and pepsin cause ulceration when mucus or bicarbonate secretion is impaired, or the mucosal coat is mechanically damaged.

Hypersecretion of Acid

  • Gastric acid secretion rises with chronic stress and spicy food, summarized as "hurry, worry, and curry."

Conditions causing hyperchlorhydria