What causes contraction of lower esophageal sphincter?

Motilin, a neurohumoral agent released into circulation from the specialized cells in the wall of intestine, is responsible for phasic LES contraction. Phasic contraction of the proximal half of the LES also occurs following swallow- or esophageal distention–induced LES relaxation.

What contracts the lower esophageal sphincter?

The lower esophageal sphincter is innervated by both parasympathetic (vagus) and sympathetic (primarily splanchnic) nerves; however, the vagal pathways are the ones that are essential for reflex relaxation of the lower esophageal sphincter (LES), such as that which occurs during transient LES relaxations.

What causes esophageal sphincter spasm?

What causes esophageal spasm? The cause of esophageal spasm is unknown. Many doctors believe it results from a disruption of the nerve activity that coordinates the swallowing action of the esophagus. In some people, very hot or very cold foods may trigger an episode.

What factors affect lower esophageal sphincter pressure?

The physiologic factors controlling lower esophageal sphincter (LES) function are interrelated in a complex fashion and include the autonomic nerve supply, gastrointestinal hormones, and specific characteristics of the circular smooth muscle at the esophagogastric junction.

What causes contraction of LES?

Electrical stimulation of the sympathetic nerves causes LES contraction that is mediated by α-adrenergic receptors [202,203]. It is likely that the sympathetic/spinal nerves innervate neurons rather than the muscles directly.

What is the main function of the lower esophageal sphincter?

The primary function of the LES is to control flow of luminal contents between the esophagus and stomach and to serve as a physical barrier against the occurrence of gastroesophageal reflux (GER) (ie, retrograde flow of gastric contents from the stomach into the esophagus).

What does the lower esophageal sphincter do?

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.

What happens when lower esophageal sphincter pressure decreases?

Reduced lower esophageal sphincter pressure resulting in gastroesophageal reflux frequently coexists with impaired esophageal clearance of refluxed gastric contents due to diminished motility in the distal two thirds of the esophagus.

What is the lower esophageal sphincter called?

The lower esophageal sphincter (LES), also known as the cardiac sphincter, is located at the bottom of the esophagus where it meets up with the stomach.

Why is the lower esophageal sphincter not a true sphincter?

However, the lower esophageal sphincter is not an anatomical but rather a functional sphincter, meaning that it acts as a sphincter but does not have a distinct thickening like other sphincters. The upper esophageal sphincter surrounds the upper part of the esophagus.

What is lower esophageal sphincter dysfunction?

The lower esophageal sphincter (LES) is a muscular ring that closes off the esophagus from the stomach. If you have achalasia, your LES fails to open up during swallowing, which it’s supposed to do.

What is the difference between achalasia and esophageal sphincter?

The esophagus is the tube that carries food from the throat to the stomach. Achalasia is a serious condition that affects your esophagus. The lower esophageal sphincter (LES) is a muscular ring that closes off the esophagus from the stomach. If you have achalasia, your LES fails to open up during swallowing,…

What happens to the esophagus between swallows?

Between swallows, the esophagus usually does not contract. The lower esophageal sphincter (or LES) is a muscle that separates the esophagus from the stomach. It acts like a valve that normally stays tightly closed to prevent contents in the stomach from backing up into the esophagus.

How does the lower esophageal opening work?

It acts like a valve that normally stays tightly closed to prevent contents in the stomach from backing up into the esophagus. When we swallow, the LES opens up (the muscle relaxes) so that the food we swallow can enter the stomach.