The Digestive Process: How Does the Esophagus Work?

Your esophagus is an important part of your digestive system and your digestive tract. Your digestive tract is a series of hollow organs that carry food from your mouth to your anus. The food you eat can't be used for energy until your digestive system breaks it down into small molecules that your body can absorb.

The role of your esophagus

When your mouth forces fluid or chewed food into your throat, your brain begins the process of swallowing. You use your voluntary nervous system to start a swallow. Your involuntary nervous system takes over your swallowing once the liquid or food enters the top of your esophagus.

Stretching from food or liquid stimulates the smooth muscles that make up the walls of your esophagus. This stimulates a dense network of nerves inside your muscles. These nerves, known as intrinsic nerves, start a coordinated muscle action called peristalsis. Peristalsis squeezes your esophageal muscles from top to bottom. This pushes food and liquid along. If you could see peristalsis, it would look like a wave passing down your esophagus.

To keep food and liquids moving in the right direction, your digestive tract has special muscles along its course called sphincters. Sphincters act like one-way valves. They relax to let food and liquid pass into your stomach and then tighten to prevent backflow, called reflux.

Common esophageal problems

When your esophagus is working correctly, you may not even be aware of it. But when you try to swallow something too big, too hot, or too cold, you can definitely feel your esophagus. You may also become aware of your esophagus when a problem develops. Some esophageal problems include:

• Achalasia. This condition means your body has problems pushing food down toward the stomach. An early symptom will be trouble swallowing (dysphagia). You may also have heartburn or chest pain.

• GERD (gastroesophageal reflux disease).  The acid made in the stomach causes a burning feeling if it creeps up into the esophagus. The main symptoms are heartburn and regurgitation. Other symptoms can include cough, wheezing, nausea, and difficulty or painful swallowing.

• Strictures. If the lining inside your esophagus becomes too narrow, food can get stuck on its way down. A narrowing of the esophagus is called an esophageal stricture. Strictures can be caused by longstanding GERD, if scar tissue forms. They are also common in an allergic condition of the esophagus called eosinophilic esophagitis.

• Cancer. Risk factors for esophageal cancer include a severe type of reflux called Barrett esophagus, tobacco use, obesity, and drinking alcohol. Symptoms are dysphagia, which slowly gets worse, and weight loss.  

Diagnosis of esophageal problems

Healthcare providers have several good ways to diagnose esophageal problems. These include:

• Endoscopy. In this procedure, a healthcare provider looks down into your esophagus by passing a thin, lighted tube, through your mouth. It has a camera attached to it. The healthcare provider can look at pictures of your digestive tract and can also take tissue samples (biopsy) of your esophagus to examine under a microscope.

• Barium swallow. In this procedure, you swallow barium. This is a substance that coats the inside of your esophagus and shows images of your esophagus on X-rays.

• Manometry. This test measures pressure inside your esophagus. It can tell your healthcare provider if your peristalsis is normal. To do the test, the healthcare provider passes a pressure-sensitive tube through your nose into your stomach. 

• pH monitoring.  A nasogastric tube is passed through your nose into the lower esophagus. This is often done for 24 hours to keep track of the pH level (the level of acid) in your esophagus. A pH probe can also be clipped onto the esophagus during an endoscopy.

Your esophagus is an important part of your digestive system. If your esophagus is doing its job right, you will hardly notice it. If you have any symptoms, such as dysphagia or heartburn, tell your healthcare provider. In most cases, they will be able to successfully diagnose and treat the problem.