STOMACH

PRERNA FOR IAS

STOMACH

1. Definition of the Stomach

The stomach is a J-shaped muscular organ of the digestive system located between the esophagus and the small intestine. It temporarily stores food, mixes it with gastric juice, and begins the digestion of proteins. The stomach produces hydrochloric acid (HCl) and digestive enzymes that break down food into a semi-liquid substance called chyme. It also destroys many harmful microorganisms present in food. Although digestion starts in the mouth, the stomach plays a major role in both mechanical and chemical digestion. Its muscular walls continuously churn food, preparing it for further digestion and absorption in the small intestine.

2. Location of the Stomach

The stomach is located in the upper left part of the abdominal cavity, just below the diaphragm. It lies between the esophagus, which carries food from the mouth, and the duodenum, the first part of the small intestine. The position and size of the stomach may vary depending on body posture and the amount of food consumed. It is protected by the lower ribs and surrounded by organs such as the liver, pancreas, spleen, and intestines. Its strategic location allows it to receive food, begin digestion, and regulate the movement of partially digested food into the intestine.

3. Parts of the Stomach

The stomach is divided into four main parts: Cardia, Fundus, Body, and Pylorus. The cardia receives food from the esophagus through the lower esophageal sphincter. The fundus is the dome-shaped upper region that stores swallowed air and food. The body is the largest central portion where most digestion and mixing occur. The pylorus is the lower region that connects to the duodenum through the pyloric sphincter. Each part performs a specialized function in digestion, ensuring food is properly stored, mixed with gastric juice, and gradually released into the small intestine for further digestion.

4. Layers of the Stomach Wall