The Mouth and The Esophagus
About The Mouth and The Esophagus
The body does a lot of work to process and digest the food we eat. It breaks food down into proteins, carbohydrates, and fats that are either absorbed or excreted as waste. Normally, all this work happens and we don't even notice... Let's look at what happens after a person takes a bite of food.
First, the food is chewed and ground up by the teeth. Saliva gets mixed in to help make the food soft and slippery. Now the food is easier to swallow. Saliva also helps balance, or neutralize acid contained in the food we eat.
Next, the person swallows. The tongue pushes food and saliva into the back of the mouth and into the throat. At the back of the throat, there is a muscular ring that opens into the esophagus. This is called the Upper Esophageal Sphincter or UES. The UES opens when you swallow and allows the food into the esophagus. When food enters the esophagus, the esophagus begins to contract and then relax in a specific rhythm. This is called peristalsis. Peristalsis helps move the food down the esophagus toward the stomach.
At the end of the esophagus, there is another muscular ring where the esophagus meets the stomach. This muscle is called the Lower Esophageal Sphincter, or LES. Usually, when someone is not eating, the LES stays closed so that food or liquid in the stomach does not move back into the esophagus. When you swallow food or liquid, the LES relaxes and opens so that food or liquid can move from the esophagus into the stomach. Then, it closes.