Gastric Secretion.swf / Sekresi Asam Lmbung.swf

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Gastric is a hollow muscular organ shaped like a big cage, consists of three parts: cardia, fundus and antrum. Food into the stomach from the esophagus through a ring-shaped muscle (sphincter), which can open and close. Under normal circumstances, the sphincter prevents re-entry of gastric contents into the esophagus. Stomach serves as a storehouse of food, which contracts rhythmically to mix food with enzymes. The cells lining the stomach produce three important substances:
- Mucus
- Hydrochloric acid
- Precursor of pepsin (enzymes that break the protein).
Mucus protects the stomach cells from damage by stomach acid and enzymes.
Any abnormalities in this mucus layer (whether due to infection by the bacterium Helicobacter pylori or aspirin), can cause damage that leads to the formation of ulcers.

Hydrochloric acid creates an atmosphere that is very acidic, which is required by pepsin to break down proteins.
High gastric acidity also acts as a barrier against infection by killing many bacteria.
Acid release is stimulated by:
- The nerves to the stomach
- Gastrin (a hormone secreted by the stomach)
- Histamine (a substance secreted by the stomach).

Pepsin is responsible for about 10% protein solution.
Pepsin is the only enzyme that digests collagen, which is a protein and the main content of the meat. Only a few substances that can be absorbed directly from the stomach (such as alcohol and aspirin) and even then only in very small quantities.

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