The article analyzes current data on the ontogenetic features of the formation of the structural and functional unit of the kidney. The process of formation and differentiation of the nephron rudiments is shown as a display of the phylogenesis of the urinary system and urinary tract. It occurs with the help of metanephrogenic cells accumulation and their subsequent transformation and differentiation. In the process of embryogenesis, the renal corpuscle and the distal tubule are allocated first, and later the proximal one. The laying of the glomeruli of capillaries occurs by intraorgan hemangiogenesis, after extraorgan arterial vessels penetrate into the thickness of the laying of the metanephros and give 1-2 orders of their branches. The structures of the anlage of the vascular and tubular poles of the renal corpuscle are in close proximity. With further formation of the tubular part of the nephron, a loop is formed. The latter is located along the collector renal tubule and drains the corresponding nephron. This section is called the distal renal tubule and the ascending part of the nephron loop. The peculiarity of the anlage and formation of the counterflow system of the kidney is that along each collector renal tubules of the juxtamedullary nephrons, there are loops of Henle of three nephrons of the same population associated with this tubule. The central position in the system is occupied by the combined renal tubule, a more sinuous ascending one adjoins it, and further to the periphery a more straightforward, descending, knee of the loop of Henle. The problems of the anlage and formation of the kidney counterflow system are considered. It is proved that cell proliferation of the fetus depends on daily fluctuations in the concentration of melatonin, a key molecule in adaptation to the day-night biorhythm. The proliferation of epithelial cells increases at night and decreases during the day, reflecting the rhythm of melatonin production. The proliferative activity of bone marrow cells, myeloid and erythroid cells is subject to the circadian rhythm. It is known that microRNAs play an important role in providing rhythms of physiological and biochemical processes in the kidneys and a key role in synchronizing biological processes, because microRNAs, being regulators of the rate of synthesis of cellular proteins, can simulate both the Tcd value and the reactivity of the phase-dependent response of biological clocks to exposure to light. In kidneys, there is a high level of expression of a variety of microRNA species: miR-192, miR0194, miR-122, miR-219, miR-132, which is a subject for further studies. Conclusion. Undoubtedly, microRNAs play an important role in ensuring the rhythms of physiological and biochemical processes in the kidneys and a key role in the synchronization of biological processes.
Full text: PDF (Ukr) 209K