The stomach is an essential component of the gastrointestinal tract, responsible for the mechanical and chemical breakdown of food into a pulpy acidic fluid called chyme. It is divided into four anatomical regions: cardia, fundus, body, and pylorus, but only three histological regions: cardia, fundus, and pylorus, as the fundus and body are histologically identical. The cardia contains cardiac glands that secrete mucus, while the fundus, the largest region, includes gastric glands that secrete digestive enzymes and mucus. The pylorus, the most distal region, contains pyloric glands that secrete mucus and neuroendocrine cells that secrete gastrin. The stomach wall consists of four main layers: mucosa, submucosa, muscularis propria, and serosa. The mucosa has a simple columnar epithelium with gastric pits leading to glands that secrete mucus and digestive enzymes. The submucosa contains dense connective tissue and blood vessels. The muscularis propria is unique with three layers of smooth muscle, aiding in digestion. The serosa consists of loose connective tissue with blood vessels and nerves. The fundic mucosa contains gastric glands with parietal cells, mucous neck cells, and chief cells, each with specific functions in digestion. The pyloric mucosa has more prominent gastric pits and glands, primarily mucus-secreting cells, with some parietal and G cells secreting gastrin.