AGE DYNAMICS OF STRUCTURAL AND CYTOCHEMICAL INDICATORS OF THE JEJUNUM OF RATS

Background. The functions of the jejunum are diverse, but all of them to some extent ensure the implementation of the two leading processes in the body: hydrolysis of nutrients that have been taken and their absorption. Objective: to study, in normal conditions, the features of the age-related formation of structural and cytochemical indices of the jejunum of rats in postnatal ontogenesis. Material and methods. The experiment was performed on 35 rats of 15-, 45- and 90-day old age. A complex of histological, histochemical, electron microscopic methods was used with subsequent morphometric and statistical analysis. Results. It was established that the structural organization of the jejunum develops intensively from the 15th to the 45th day, which is probably due to the transition from dairy to definitive type of nutrition. Conclusions. The microvillous epithelium is already completely formed by the 15th day and has a high structural and cytochemical organization providing an intensive level of parietal digestion right after birth and absorption of the monomers that form.