Changes of Intestinal Absorptive Cells During Maturation: An Electron Microscopic Study of Prenatal, Postnatal, and Adult Guinea Pig Ileum.

摘要

Maturation of intestinal epithelial cells in the distal ileum of the guinea pig is accompanied by an increase in length and number of microvilli of villus absorptive cells; in the three age groups studied microvilli reach their maximal length in the mid-villus area and become shorter at the villus tip, their width remaining essentially unchanged. Mitochondria of villus epithelial cells change their shape and size and increase in number with age. Prenatally they are large; two days after birth greatly increased numbers of small and large forms are present. Only large numbers of small forms are seen in the adult. In contrast crypt cell mitochondria are large at all stages. The complexity and numbers of cytoplasmic membrane systems increase with age and are modified by villus location. Monoparticulate glycogen deposits shift dramatically after birth and are absent in the adult. A correlation of structural changes to altered functional demands is attempted. It is suggested that the intraluminal intestinal environment exerts a morphogenic effect at the ultrastructural level. (Author)