gut lumen. columnar epithelial cells

absorption absorptive anatomical anatomy antagonism bacteriocin basolateral bowel cell colon diagram digestion digestive duodenum enterocyte enterocytes enzymes epithelial epithelium gastric gastrointestinal gut health healthy human intestinal intestine lining lumen medical metabolism mucosa neutralization organ pathogen prebiotic probiotic science section small stomach structure surface system tissue toxin tract unattached villi villus