The small bowel

The small bowel, or small intestine, is the long and tortuous central section of the intestinal tract that is 2m long and contains millions of villi, microscopic finger like projections that increase the surface area of the gut and allow absorption of water and nutrients. The beginning of the small bowel is caused the duodenum and this can be seen during a gastroscopy where biopsies can diagnose coeliac disease, a common cause of malabsorption. The central part of the small intestine, comprising the jejunum and ileum are less accessible but the last part of the ileum, where Crohn’s disease often occurs, can be seen and a biopsy taken as part of a colonoscopy. Alternative ways of investigating the small intestine include scanning with ultrasound, CT or MRI scans or using capsule enteroscopy, a modern technology whereby a swallowed camera pill transmits images to a recorder worn by the patient as the capsule passes through the intestine over the course of several hours.

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