[Ultrastructure of the enterocytes of the upper 3d of the villi of murine small intestine].

The enterocytes of the upper one-third of the villi of duodenum, ileum and jejunum of mice were investigated with the electron microscope. It was found that enterocytes moving to the top of the villus underwent regular structural rearrangements that involve the appearance of triangular dilatations of the intercellular spaces at the cell base, condensation of the mitochondrial matrix, reduction of ergastoplasmic reticulum and dictyosome hypertrophy. It is suggested that enterocytes leave the top of the villus as structurally and functionally valid cells.