Text E. The stomach.

The word stomach is derived from the Latin stomachus which is derived from the Greek word stomachos, from stoma, "mouth". The words gastro- and gastric (meaning related to the stomach) are both derived from the Greek word gaster.

The stomach is located at the bottom of the chest; just below the oesophagus.It is on the left upper part of the abdominal cavity. The top of the stomach lies against the diaphragm. The organ behind the stomach is the pancreas.

Two sphincters, keep the contents of the stomach contained. They are the esophageal sphincter dividing the tract above, and the pyloric sphincter dividing the stomach from the small intestine.

The stomach is surrounded by the networks of blood vessels and nerves which regulate both the secretions activity and the motor activity of its muscles.

In humans, the stomach has a relaxed, empty volume of about 45 ml. It normally expands and holds about 1 liter of food, but will hold as much as 2-3 liters (whereas a newborn baby will only be able to retain 30ml).

The stomach's first job is to accept and store the food that enters it.In response to the arrival of food, glands present in the lining of the stomach produce stomach acid (or gastric acid) - another digestive juice. Muscles in the wall of the stomach help to move the food and acid around and mix thoroughly.Stomach acid helps to break down the food further into smaller, easier to digest fragments. The acid also kills bacteria contained in the swallowed food or saliva.By the time food is ready to leave the stomach, it has been processed into a thick liquid. Finally, muscular movements in the lower part of the stomach push this partly-digested food down towards the small intestine.

Some medical problems of the stomach include:

· Peptic ulcers

· Gastric cancer

Дата добавления: 2015-07-20