The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). One of its main functions is to produce hormones that help regulate the body's metabolism (the process that turns food into energy). These hormones are called triiodothyronine (T3) and thyroxine (T4). Many of the body's functions slow down when the thyroid doesn't produce enough of these hormones.
Esophageal spasm is a disorder of the rhythmic waves of muscular contractions (peristalsis) of the esophagus. The cause of this disorder is not known. Symptoms include chest pain and difficulty swallowing.
1 Chronic irritation from reflux is the usual cause of esophageal strictures. 2  Achalasia: A rare disease in which the lower esophageal sphincter does not relax properly. 3  Difficulty swallowing and regurgitation of food are symptoms. 4  Esophageal cancer: Although serious, cancer of the esophagus is uncommon.hey keep food and secretions from going down the windpipe. The lower esophageal sphincter (LES) is a bundle of muscles at the low end of the esophagus, where it meets the stomach. When the LES is closed, it prevents acid and stomach contents from traveling backwards from the stomach.