Enterocytter

Enterocytter, or enterocytes in English, are the predominant absorptive cells of the epithelial lining in the small intestine. They are tall, columnar cells arranged along the villi and organized into a polarized epithelium with an apical brush border formed by densely packed microvilli, and a basolateral membrane connected by tight junctions. The brush border enzymes, including lactase, sucrase, and maltase, complete luminal digestion, while membrane transporters mediate uptake of nutrients.

Function: They mediate absorption of nutrients, minerals and water. Glucose and galactose are transported into cells via SGLT1 on the apical surface, with fructose via GLUT5; all are released into the bloodstream via basolateral transporters such as GLUT2. Amino acids and small peptides are absorbed by specific transporters; lipids are emulsified by bile salts and absorbed as fatty acids and monoglycerides, reassembled into triglycerides in the endoplasmic reticulum, packaged into chylomicrons, and transported via the lymphatic system. Sodium and water absorption is coupled to nutrient uptake, and the Na+/K+ ATPase on the basolateral membrane maintains the necessary electrochemical gradients.

Development and turnover: Enterocytes differentiate from stem cells in the crypts of Lieberkühn, migrate up the villus, and are shed after approximately 3–5 days.

Clinical relevance: Damage to enterocytes compromises digestion and absorption, as seen in celiac disease, infectious enteritis, and other malabsorption syndromes; their integrity is essential for barrier function and immune surveillance.