human small intestine

mucosa submucosa muscularis adventitia small intestine digestion absorption digestive system duodenum jejunum ileum intestinal villi goblet cells absorptive connective tissue anatomy health nature microscope cell education clinical blood vessels basal membrane lymphocytes medical publishing scientific photographs medical cellular histology embryology human structural basic medicine micrography nuclei stroma cytoplasm mucus serous human body organs fibrous histopathology