Esophagus
The role of the esophagus is to convey boluses of food from the pharynx to the stomach.
- The esophagus begins as an extension of the pharynx (throat) in the back of the oral cavity.
- It then courses down the neck next to the trachea, and penetrates the diaphragm to connect with the stomach in the abdominal cavity.
- Strong muscles cause rhythmic contractions known as peristalsis than helps the food move through the esophagus toward the stomach.
- The bolus enters into the stomach through the esophageal sphincter when it is relaxed.
- The upper and lower sphincters are closed except during swallowing, which prevents constant entry of air from the oral cavity, or reflux of stomach contents.
- Common disorders involving the esophagus include heartburn and gastroesophageal reflux disease (GERD).