The epithelial lining varies significantly along the GI tract, reflecting its functional adaptation:
Esophagus: Lined with stratified squamous epithelium to protect against abrasion. Stomach: Simple columnar epithelium with gastric pits and glands for secretion of digestive enzymes and hydrochloric acid. Small intestine: Simple columnar epithelium with villi and microvilli to enhance nutrient absorption. Large intestine: Simple columnar epithelium with numerous goblet cells for mucus secretion to facilitate fecal passage.
