Swallowing is process that we give little, if any, thought to when it is normal. However, when a disorder occurs, it can produce great anxiety for the patient.
Swallowing is a complex process that requires precise coordination between many nerves and muscles. Normal Swallowing occurs in three phases:
- Oral or preparatory phase of swallowing. This phase involves placing food or drink in the mouth, chewing and moistening it with saliva, and positioning it in the mouth so it can be swallowed.
- Pharyngeal phase of swallowing. This phase starts with closing the lips and clenching teeth so that nothing will leak from the mouth. Next, the tongue pushes the food from the mouth to the throat (pharynx). The voice box (larynx) closes so no food can enter the breathing passages or lungs. Finally, a special muscle called a sphincter, located where the throat and esophagus join, opens so the food can move into the esophagus.
- Esophageal phase of swallowing. The esophagus is a tube-like organ that connects the mouth and throat with the stomach. At each end, the tube is closed by the contraction of special muscles called sphincters. The esophagus and sphincter muscles are designed to move what is swallowed to the stomach. They also prevent stomach contents from moving back up into the esophagus and breathing passages. Food that enters the esophagus is squeezed down to the stomach by a special muscle contraction called peristalsis. Peristalsis is like placing your fingers at the closed end of a tube of toothpaste and using them to squeeze all the toothpaste out the open end. The sphincter muscle at the lower end of the esophagus opens so the food can enter the stomach. Once the food is in the stomach, the muscle closes so the food and stomach acid cannot move back up the esophagus.