The upper gastrointestinal tract consists of the esophagus, larynx, pharynx, and stomach. The esophagus is a muscular tube that carries food from the mouth to the stomach. The larynx and pharynx are located above the esophagus and play critical roles in breathing, speaking, and swallowing.
Here is the download link for a pdf version: Not Available Lpr Physiology Book Pdf
The lower esophageal sphincter (LES) is a ring-like muscle that separates the esophagus and stomach. The LES plays a crucial role in preventing stomach acid from flowing back up into the esophagus. In a normal physiological state, the LES relaxes to allow food to enter the stomach and then contracts to prevent reflux. The upper gastrointestinal tract consists of the esophagus,