When the liquid content of the stomach refluxes into the esophagus, we can say that we have a condition common in gastroesophageal reflux disease. It is believed that the acid is the component of the stomach liquid that does the most harm to the lining of the esophagus. The refluxed liquid also contains pepsin and bile, but their role in injuring the esophagus is not so clear as in acid's case.

Once gastroesophageal reflux disease appeared, it usually lasts all life long. Even if the esophagus has healed, if the treatment is stopped, the injury will return in most patients soon. The treatment for gastroesophageal reflux disease usually needs to be continued indefinitely.

It is known that the reflux of the stomach's liquid contents into the esophagus can appear in most normal people, but in patients with gastroesophageal reflux disease the refluxed liquid contains more acid and remains in the esophagus longer.

Usually, most reflux occurs during the day, when we are in upright position. This position makes the liquid to flow back into the stomach, due to gravitation. When we are awake, we swallow often, and saliva travels down the esophagus, neutralizing the small quantity of liquid that remains in the esophagus after the effect of gravity and repeated swallowing. The saliva contains bicarbonate, and that is why it can have a neutralizing effect for acid.

If a reflux takes place during the night, while sleeping, it will probably cause a greater damage effect to the esophagus because, swallowing stops, the secretion of saliva is reduced and gravity is not in effect.

The gastroesophageal reflux disease can cause serious problems during pregnancy, and also in patients that have diseases that weaken the esophageal muscles, such as mixed connective tissue or scleroderma.

There are a lot of factors that can cause the gastroesophageal reflux disease.

The lower esophageal sphincter is a specialized ring of muscle that is surrounding the lower-most end of the esophagus where it joins the stomach. It is known that the muscle that makes up the lower esophageal sphincter is active most of the time. It is contracting and closing off the passage from the esophagus into the stomach. It is this closing that prevents reflux, and there are a few situations of abnormalities of the lower esophageal sphincter that must be mentioned.

If the lower esophageal sphincter performs a weak contraction, that will reduce the ability of preventing the reflux.

There can also appear abnormal relaxations of the lower esophageal sphincter, and these

allow reflux to occur more easily.

Hiatal hernias also contribute to the gastroesophageal reflux disease. As a result of the hiatal hernia, small part of the stomach and the lower esophageal sphincter come to lie in the chest. Normally, the lower esophageal sphincter is at the level of the diaphragm.

The diaphragm that surrounds the lower esophageal sphincter seems to be important in preventing reflux. Effects of the diaphragm and lower esophageal sphincter appear at the same location in patients without hiatal hernia. The sum of the pressures generated by them prevent the reflux. In people with hiatal hernia, the diaphragm and lower esophageal sphincter continue to generate pressure, but at different levels, and in this way, the pressure barrier is decreasing.

In hiatal hernia disease, there exist a sac, which is a small pouch of stomach above the diaphragm .It is full of acid, and when it is pinched off from the esophagus above by the lower esophageal sphincter and from the stomach below by the diaphragm, it can reflux easier during a swallow or a relaxation.

It is known that the esophagus connects the stomach obliquely, and due to this, a flap of tissue is formed between the stomach and esophagus. It is believed that this tissue is acting like a valve and preventing reflux. When hiatal hernia is present, the valve-like flap disappears, or is distorted and will not help to prevent the reflux.

Esophageal contractions are very important, they are caused by the act of swallowing. During this, food, saliva or whatever there is in the esophagus is pushed into the stomach, and if there is a abnormality with this contraction, refluxed acid is not pushed back into the stomach.

Some abnormalies that can appear: the waves of contraction may die out before they reach the stomach, or waves of contraction do not begin after each swallow, or the pressure generated by the contractions is too slow to push the acid back into the stomach.

These are frequent in patients that have gastroesophageal reflux disease.

Usually, in most cases reflux during day appears after meals, and this probably happens because of the transient lower esophageal sphincter relaxations. There were seen patients that are having an extremely slowly digestion, and it is known that during this period the reflux has greater chances to appear.