Why does food not simply drop to the stomach?

The esophagus is a muscular tube that connects the throat to the stomach. It carries food from the mouth to the stomach. The esophagus has two sphincters, or circular muscles, that act as valves to keep food from coming back up. The upper esophageal sphincter (UES) is located at the top of the esophagus, and the lower esophageal sphincter (LES) is located at the bottom.

When you swallow food from the mouth, it enters the esophagus. The muscles in the esophagus contract behind the food, which moves it down the esophagus and into the stomach. The UES and LES relax to allow food to pass through, and then they contract again to keep food from coming back up.

There are a few things that can cause food to not simply drop to the stomach. One is a condition called achalasia, which is a weakness or paralysis of the muscles in the esophagus. This can cause food to become stuck in the esophagus and not be able to pass through. Another condition is a hiatal hernia, which is a condition in which part of the stomach protrudes through an opening in the diaphragm. This can also cause food to become stuck in the esophagus.