GENERAL HISTOLOGY

Detailed explanation-1: -Normal LES function allows food transit from the esophagus into the stomach and prevents the reflux of gastric contents back into the esophagus. Improper relaxation of the LES can lead to food entrapment in the esophagus, achalasia, and an increased risk of esophageal squamous cell carcinoma.

Detailed explanation-2: -The LES stays closed except during swallowing, when it allows food to pass from the esophagus into the stomach. When the LES is closed, it prevents the backflow (reflux) of stomach acid into the esophagus. If the LES does not close tightly enough, stomach acid backs up into the esophagus, causing heartburn.

Detailed explanation-3: -At the junction between the stomach and esophagus is the lower esophageal sphincter. This muscular sphincter acts as a valve that normally keeps food and stomach acid in the stomach, and prevents the stomach’s contents from regurgitating back into the esophagus.

Detailed explanation-4: -A “valve” called the lower esophageal sphincter (LES) is located just before the opening to the stomach. This valve opens to let food pass into the stomach from the esophagus and it prevents food from moving back up into the esophagus from the stomach.

Detailed explanation-5: -The LES is a 3-4 cm tonically contracted smooth muscle segment located at the esophagogastric junction (EGJ) and, along with the crural diaphragm forms the physiological EGJ barrier, which prevents the retrograde migration of acidic gastric contents into the esophagus[17].