Acid Reflux Disease Basics

Introduction

Gastroesophageal reflux disease (GERD) is a condition in which acids from the stomach move backward into the esophagus (an action called reflux). Reflux occurs if the muscular actions in the esophagus or other protective mechanisms fail.

Click the icon to see an animation about heartburn.

The hallmark symptoms of GERD are:

• Heartburn: a burning sensation in the chest and throat.
• Regurgitation: a sensation of acid backed up in the esophagus.

Although acid is a primary factor in damage caused by GERD, other products of the digestive tract, including pepsin and bile, can also be harmful.

Heartburn is a condition where the acidic stomach contents back up into the esophagus causing pain in the chest area. This reflux usually occurs because the sphincter muscle between the esophagus and stomach is weakened. Standing or sitting after a meal can help reduce the reflux which causes heartburn. Continuous irritation of the esophagus lining as in gastroesophageal reflux disease is a risk factor for the development of adenocarcinoma.

The Esophagus

The esophagus, commonly called the food pipe, is a narrow muscular tube about nine and a half inches long. It begins below the tongue and ends at the stomach. The esophagus is narrowest at the top and bottom; it also narrows slightly in the middle. The esophagus consists of three basic layers:

• An outer layer of fibrous tissue.
• A middle layer containing smoother muscle.
• An inner membrane, which contains numerous tiny glands.

Click the icon to see an image of the esophagus.

When a person swallows food, the esophagus moves it into the stomach through the action of peristalsis, wave-like muscle contractions. In the stomach, the starch, fat, and protein in food are broken down by acid and various enzymes, notably hydrochloric acid and pepsin. The lining of the stomach has a thin layer of mucus that protects it from these fluids.

If acid and enzymes back up into the esophagus, however, its lining offers only a weak defense. The esophagus is protected using specific muscles and other factors.

The most important structure protecting the esophagus may be the lower esophageal sphincter (LES). The LES is a band of muscle around the bottom of the esophagus where it meets the stomach.

• The LES opens after a person swallows to let food enter the stomach and then immediately closes to prevent regurgitation of the stomach contents, including gastric acid.
• The LES maintains this pressure barrier until food is swallowed again.