How does food move through the esophagus?

Food moves through the esophagus through a process called peristalsis. Peristalsis is a series of involuntary, rhythmic muscle contractions that propel food from the pharynx (throat) to the stomach.

* Swallowing: The act of swallowing is initiated when food or liquid is placed in the mouth. The tongue forms the food into a ball called a bolus, which is then pushed back into the pharynx by the muscles of the tongue and cheeks.

* Pharyngeal Peristalsis: Once the bolus is in the pharynx, a series of involuntary muscle contractions begins. These contractions move the bolus from the pharynx into the esophagus.

* Esophageal Peristalsis: As the bolus enters the esophagus, peristalsis continues. The muscles of the esophagus contract and relax in a wave-like pattern, propelling the food downward toward the stomach.

* Esophageal Sphincter: At the lower end of the esophagus, there is a muscular ring called the esophageal sphincter. When food pushes the esophageal sphincter, it is relaxed, allowing food to pass through into the stomach.

The entire process of peristalsis from swallowing to propulsion occurs in a matter of seconds, allowing efficient transport of food bolus, without any force of gravity. However, gravity can accelerate peristalsis if a person is in an upright position or if the food mass is large. Certain factors can affect the process of peristalsis and lead to problems with swallowing or esophageal motility disorders.