In histology, the digestive system refers to the microscopic study of the tissues and organs that make up the gastrointestinal tract and associated glands (e.g., salivary glands, liver, pancreas). It focuses on the layered structure of the digestive tract walls (mucosa, submucosa, muscularis, serosa/adventitia) and the specialized cells within each layer that perform digestion, absorption, and secretion. Histological examination reveals the unique adaptations of each part of the digestive system to its specific function in processing food.