Vol 140, No 5 (2011)

This review summarizes the results of the study of the provisionality phenomenon in the development of the organs of the urinary system (mesonephros, metanephros) in viviparous (human, rat) and oviparous (bird) amniotes, human organs of mixed origin (pituitary, ovary, stomodeum) reparative regeneration of supporting tissues (in humans and Syrian hamster), morphogenesis of primary hepatic cancer developing against the background of superinvasive opisthorchiasis. It is shown that during the development of tissues and organs, the stages of provisional and definitive histo- and organogenesis could be determined; saltatory mechanism is typical for embryonic organogenesis (formation of cartilaginous skeletal primordia, meso- and metanephrons) and foci of oncogenesis. Transformation zones of the type of tissue organization in the epithelium are located in the areas of contacts of the derivatives of different embryonic primordia. Mechanism of transformation of the epithelial layer of stomodeum and Rathke's pouch is provided by local activation of apoptosis and by the formation of the epithelial cells of a qualitatively new generation.

The regularities of the formation of the undifferentiated renal tubules in the definitive kidney were studied in 174 human embryos and fetuses at 4.5 to 40 gestational weeks. On the basis of the study of morphological and morphometrical parameters of these tubules, it was shown that the increase of the average tubular crossectional area was associated with the consecutive formation of the nephrons of the definitive kidney and the differentiation of the segments of their tubular portions. The increase of the proportion of the epithelium in the structure of undifferentiated tubule is determined by the segregation of the proximal and distal tubules within the forming nephrons. The sequence of the initial stages of the renal tubule differentiation is dictated by the ergontic correlations; it developes from the proximal tubule to the distal one and is different from the succession of their formation in the process of the early nephronogenesis.

The complex study of the physical development of boys and girls aged 11-18 years of native and newly come population of Khanty-Mansiysk-Ugra Autonomous Region was performed. It was found that the native population had higher mass of fat component in all the age groups as compared to that of the newly come population. The data obtained reflect the regional peculiarities of the growth processes of the children of native and newly come population. These data help to reveal the mechanisms providing adaptive character of development at the pubertal stage the ontogenesis.