3d close-up intestinal villi. intestine lining. microscopic villi and capillary. human intestine. concept

absorption absorptive anatomy background belly bile biology bowel cancer care cells cholesterol closeup colon digestion digestive duodenum enterocytes enzymes epithelial epithelium gastric gastrointestinal gut health histology human intestinal intestine large lining lumen medical medicine microscopic microvilli minerals mucosa nutrients nutrition small stomach surface system tissue tract villi villus