Gastro-oesophageal Reflux Disease
A failure of the lower oesophageal sphincter barrier lets acid reflux into an oesophagus not built to tolerate it, so the symptom pattern follows directly from where and how often that acid tracks backwards.
First principles
GORD is a barrier failure, not an excess-acid disease
The lower oesophageal sphincter (LOS) normally stays contracted between swallows, preventing gastric contents moving retrograde. GORD arises when this barrier fails: through transient LOS relaxations, a hiatus hernia that uncouples the sphincter from the diaphragmatic crura, or raised intra-abdominal pressure from obesity or pregnancy pushing against a competent-but-overwhelmed sphincter. Gastric acid secretion is usually entirely normal; what has changed is exposure time of the oesophagus to acid it was never designed to encounter. This is why the disease is defined by reflux frequency and duration, not by acid output.
Educational content pending clinical review. Not medical advice.