Nutrition Science and Everyday Application - beta v 0.1

Disorders of the GI Tract
Now that we’ve covered the structures and functions of the digestive system, it should
be clear that the digestion of food requires the coordinated action of multiple organs. If
any of these aren’t working well, it can wreak havoc on the function of the entire system
and interfere with health and quality of life. Let’s look at some common discomforts and
disorders of the GI tract.
HEARTBURN AND GASTROESOPHAGEAL REFLUX
Heartburn is a burning, often painful, sensation in the chest (behind the breastbone) or
throat. Heartburn is caused by gastroesophageal reflux (GER), when the acidic chyme in the
stomach escapes back into the esophagus and even into the mouth. Normally, this reflux
is prevented by the lower esophageal sphincter (a tight ring of muscle) that sits between
the esophagus and stomach. The muscles of the sphincter contract to keep it closed, only
relaxing to allow food boluses and liquid to pass from the esophagus into the stomach
and then quickly contracting again to keep the contents of the stomach separate from
the esophagus. The lower esophageal sphincter can be weakened because of increased
pressure on the abdomen from obesity or pregnancy, exposure to tobacco smoke, and some
medications, so the risk of GER is increased in these scenarios.
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