All About the Stomach

Your stomach is as an organ needed for digestion. Digestion is the process of breaking down food into its smallest particles so your body can take in nutrients. The process of digestion involves the mixing of food, its movement through the digestive tract, and the chemical breakdown of the large molecules of food into smaller molecules. Digestion of food begins in the mouth. Teeth break the food into smaller particles and an enzyme in saliva begins to break down starches into simple sugars. Digestion continues in the stomach.  

When it's empty, your stomach looks like an unexpanded J-shaped balloon. It's capable of making itself smaller and larger to accommodate anything from a snack to a 7-course dinner.

Different sections

The top part of the stomach makes gastric acid and a digestive enzyme, pepsin. The lower part of the stomach is more muscular and mixes food with the digestive fluids. With the exception of alcohol and some drugs, the soaking up of nutrients does not take place in the stomach. When the gastric content is completely mixed and liquefied, it passes into the small intestine, where more digestion of proteins, sugars, and fats happens and where the soaking up of nutrients begins. By the time the contents pass through the entire small intestine to enter the colon, digestion is complete and the nutrients have been completely soaked up. The colon draws out water and some materials like vitamins K and B-12 and begins to form stool.

Common problems

Common problems of the stomach include:

  • Gastroesophogeal reflux disease (GERD). This is a problem of the esophagus and the most common sign of this condition is heartburn. The circular muscle between the esophagus and stomach is the lower esophageal sphincter. Its failure to close properly causes heartburn. This allows the return of food and stomach juices into the esophagus. When refluxed stomach acid touches the lining of the esophagus, it causes a burning sensation in the chest or throat called heartburn. Occasional heartburn is common but does not necessarily mean that you have GERD. If it occurs more than twice a week, it may be GERD and can lead to more serious health problems. It can be caused by a hiatal hernia (when the upper part of the stomach is above the diaphragm); too much alcohol use; being overweight; pregnancy; and smoking. GERD may be caused by nonacid reflux as well. 

  • Gastritis. Gastritis, or inflammation of the stomach lining, is a symptom, not a disease. It can be caused by drinking too much alcohol, prolonged use of some medicines like aspirin or ibuprofen, by the bacterium Helicobacter pylori (H. pylori), or some diseases. The most common symptoms are abdominal upset or pain, belching, bloating, nausea, vomiting, and a feeling of burning in the upper abdomen. Sometimes it causes the stomach to bleed. This needs immediate medical attention.

  • Peptic ulcer. A peptic ulcer is a sore on the lining of the stomach or duodenum. The duodenum is the beginning of the small intestine. Peptic ulcers can be caused by bacterial infection with H. pylori; by long-term use of nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen; and, in rare cases, by cancer of the stomach or pancreas. Peptic ulcers are not caused by stress or eating spicy food, but these can make ulcers worse. The most common symptom of a peptic ulcer is a dull, gnawing ache in the stomach that comes and goes for a period of time. The ache occurs 2 hours to 3 hours after eating or in the middle of the night, when the stomach is empty. The pain is made better by eating or taking antacid medications. Some people have no symptoms. A sudden, sharp stomach pain or bloody or black stools or blood in vomit means that medical care is needed right away.