esophageal sphincter
Quick Summary
The esophageal sphincter is a ring of muscles that controls the passage of food and other substances. There are two main esophageal sphincters: the upper and lower esophageal sphincters.
The upper esophageal sphincter is located at the top of the esophagus, near the cricoid cartilage. It is also known as the cricopharyngeus muscle and is composed of striated muscle.
The lower esophageal sphincter (LES) is located at the bottom of the esophagus, where it passes through the diaphragm to connect with the stomach. It is made of smooth muscle and is normally kept closed, relaxing only to allow food to enter the stomach, release gas (belching), or during vomiting. The LES plays a crucial role in preventing stomach contents from refluxing back into the esophagus.1
Disorders of esophageal motility, such as achalasia, can affect the function of these sphincters, leading to difficulty swallowing and impaired emptying of the esophagus.2
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esophagus…by muscular constrictions known as sphincters; at the anterior, or upper, end is the upper esophageal sphincter, and at the distal, or lower, end is the lower esophageal sphincter.
Read More…by muscular constrictions known as sphincters; at the anterior, or upper, end is the upper esophageal sphincter, and at the distal, or lower, end is the lower esophageal sphincter.
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human digestive systemPharynxThe cricopharyngeal muscle, or upper esophageal sphincter, which has kept the esophagus closed until this point, relaxes as the bolus approaches and allows it to enter the upper esophagus. The pharyngeal peristaltic contraction continues into the esophagus and becomes the primary esophageal peristaltic contraction.
Read MoreThe cricopharyngeal muscle, or upper esophageal sphincter, which has kept the esophagus closed until this point, relaxes as the bolus approaches and allows it to enter the upper esophagus. The pharyngeal peristaltic contraction continues into the esophagus and becomes the primary esophageal peristaltic contraction.
Read More