Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones.
In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication, a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food. After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. As these two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the damaging effects of the chemicals. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes.
Stomach cancer, or gastric cancer, refers to cancer arising from any part of the stomach. Stomach cancer causes about 800,000 deaths worldwide per year. Prognosis is poor (5-year survival <5 to 15%) because most patients present with advanced disease.
The stomach is an important organ in the body. It plays a vital role in digestion of foods, releases various enzymes and also protects the lower intestine from harmful organisms. The stomach connects to the esophagus above and to the small intestine below. It is intricately related to the pancreas, spleen and liver. The stomach does vary in size but its J shape is constant. The stomach lies in the upper part of the abdomen just below the left rib cage.
Gastropathy is a general term used for stomach disease. Examples including the name include portal hypertensive gastropathy and Ménétrier's disease, also known as "hyperplastic hypersecretory gastropathy". However, there are many other stomach diseases that don't include the word "gastropathy" such as gastric or peptic ulcer disease, gastroparesis, and dyspepsia.