Stomach

The stomach is a muscular organ located in the upper abdomen, just below the rib cage, on the left side of the body. Its primary function is to store, digest, and break down food that has been ingested before it is further processed in the small intestine. The stomach plays a crucial role in the digestive process by secreting gastric juices containing acids and enzymes necessary for the breakdown of food molecules.

• Gastric Lining: The inner lining of the stomach is composed of specialized cells that secrete gastric juices, including hydrochloric acid (HCl) and digestive enzymes such as pepsin. These substances help break down proteins, fats, and carbohydrates into smaller molecules that can be absorbed in the intestines.
• Mucous Cells: The stomach also contains mucous-secreting cells that produce a thick layer of mucus, which coats the stomach lining and protects it from the corrosive effects of gastric acid.
• Muscular Layers: The walls of the stomach are made up of three layers of smooth muscle tissue arranged in longitudinal, circular, and oblique orientations. These muscles contract and relax in a coordinated manner to churn and mix food with gastric juices, forming a semi-liquid substance known as chyme.
• Sphincters: The stomach is connected to the esophagus by the lower esophageal sphincter (LES), which opens to allow food to enter the stomach and then closes to prevent the backflow of stomach contents into the esophagus. At the lower end of the stomach, there is another muscular ring called the pyloric sphincter, which regulates the passage of chyme from the stomach into the small intestine.
• Gastric Emptying: Once food has been sufficiently processed in the stomach, it is gradually emptied into the small intestine through the pyloric sphincter. Gastric emptying is controlled by various factors including the volume and composition of the meal, the presence of hormones and neural signals, and the contraction of stomach muscles.

Disorders and conditions that can affect the stomach include:

• Gastritis (inflammation of the stomach lining)
• Peptic ulcers (open sores in the stomach lining)
• Gastroenteritis (stomach flu)
• Gastric cancer
• Gastroparesis (delayed stomach emptying)
• Gastroesophageal reflux disease (GERD)
• Helicobacter pylori infection (bacterial infection associated with peptic ulcers)