intestinal villus. different between villi and microvilli

intestinal villus villi microvilli cross duodenum submucosa mucosa muscularis layer lymph capillary lacteal blood vessel closeup columnar epithelium enterocyte celiac disease intestine gut anatomy gastrointestinal bowel tract digestive medical absorption health digestion epithelial lining tissue histology cell small biology gastric wall anatomical surface diagram structure vector microscopic ileum internal coeliac network capillaries goblet crypts