The flap between the esophagus and the stomach is called the lower esophageal sphincter (LES).
The LES acts as a valve, controlling the passage of food from the esophagus into the stomach and preventing stomach contents, including stomach acid, from flowing back up into the esophagus. This backflow is known as acid reflux and can cause heartburn and, over time, gastroesophageal reflux disease (GERD).
Function of the Lower Esophageal Sphincter
- One-way valve: The LES is designed to open and allow food to pass from the esophagus into the stomach.
- Prevents reflux: It remains closed most of the time to prevent the acidic contents of the stomach from backing up into the esophagus.
- Muscle control: The LES is a ring of muscle that contracts to close the opening between the esophagus and stomach and relaxes to allow food to pass through.
Implications of a Malfunctioning LES
When the LES doesn't function correctly, it can lead to several problems, including:
- GERD (Gastroesophageal Reflux Disease): A common condition where stomach acid frequently flows back into the esophagus, causing irritation and inflammation.
- Heartburn: A burning sensation in the chest caused by stomach acid refluxing into the esophagus.
- Esophagitis: Inflammation of the esophagus, often caused by chronic acid exposure.
Therefore, the LES is a crucial component of the digestive system, preventing acid reflux and protecting the esophagus from damage.
