The Stomach

FUNCTION & STRCTURE

The stomach is a thick-walled, "J" shaped organ that lies on the left hand side of the body under the diaphragm.
The stomach functions to turn the bolus, a mass of chewed food, into a semi-liquid mass called the ACID CHYME through the process of churning it repeatedly.
The stomach empties the acid chyme it produces into the first part of the small intestine called the DUODENUM.
- This emptying process is controlled by a PYLORIC SPHINCTER at the end of the stomach. It functions just as the cardiac sphincter does.

STRUCTURE:

The stomach is made up of three layers of muscle that contract to churn and mix the contents within it.
- Hunger pain is felt when the stomach churns without any food or bolus.
There is also a mucus lining that lines the sides of the stomach and contains gastric glands that produce gastric juice.
- Gastric juice contains HCl and pepsinogen and when they combine together pepsinogen forms an enzyme known as pepsin.
Pepsin is a hydrolytic enzyme that breaks down proteins into smaller chains of amino acids called peptides
HCl in gastric juice is also highly corrective and kills bacteria in food and functions to break it down.

The inner wall of the stomach is protected by a layer of mucus made in mucosal cells.
If the highly corrosive HCl in gastric juice does penetrate the stomach wall, the enzyme pepsin will begin to break down and digest the lining and stomach itself.
- This will result in the formation of an open sore on the wall of the stomach
- Too much gastric juice can cause ulcers, which are severe open soares
  - When this occurs it can cause too much nerve stimulation (stress) to build up in this organ and lead to the stomach to begin to over-secret gastric juice.
However, the number one cause of ulcers in actually bacterial infection that can impair mucosal cells from producing mucus to line the walls of the stomach.