Variation of small intestinal morphology with age.

A study of small intestinal three-dimensional morphology from 85 childhood necropsies, using the dissecting microscope, has shown that there is a variation in morphology with age. While finger-like villi occurred frequently in the small intestine of neonates, particularly in the ileum, broader villi occurred more frequently in children aged between 5 months and 5 years, particularly in the proximal small intestine. However, in children over the age of 5 years, finger-like villi were observed more frequently, right along the length of the small intestine. This alteration in morphology in the early weeks of life is probably due to some change in the luminal environment developing shortly after birth, and it is suggested that bacterial colonization of the small intestine, and the response of the host to this, is responsible for these changes.