At the lower end of the gullet there is a ring of muscle called the lower oesophageal sphincter (LES) which normally acts as a valve to prevent acid contents of the stomach leaking (refluxing) into the lower part of the oesophagus (see Fig 1).
However, if the LES fails to function properly, stomach acid and bile juices can flow into the oesophagus, giving rise to heartburn and various other symptoms of GORD (see Fig.2).
Unlike stomach cells which secrete a special mucous to protect them from acid digestion, the lining of the oesophagus has no such protection and is therefore vulnerable to the effects of acid and bile salts. This can result in inflammation and – if prolonged – ulceration and bleeding.
It is not known why the lower oesophageal sphincter (LES) fails to work properly, but we know that GORD is more common in males, during pregnancy, smokers, heavy drinkers and in those who are obese. Symptoms may also be more marked when bending forwards and lying down. In addition, if you have a hiatus hernia (when part of the stomach protrudes through the diaphragm), you have an increased chance of developing reflux disease.