[Arterial and venous vascularization of cow's ureter in the fetal and neonatal periods].

Investigations of ureter perfusion in cattle during fetal and neonatal period were carried out on 84 fetuses and 10 female newborn cattle. The fetuses 78-1000 mm long were of the 9th-40th week of pregnancy, whereas the newborn ones were 2 or 14 days old. Pelvis blood vessels were filled with rubber latex stained with pigment. This was obtained with the help of a special automatic injector made by ourselves. After coagulation of injection substance the blood vessels were examined under a stereoscopic microscope, some microsurgical instruments adapted to our needs were used. The analysis of morphology and artery developmental markers as well as of ureter veins was carried out with reference to its proximal, middle and distal parts. On the basis of the results it was noticed that transformations of investigated vessels referred mainly to their number. place, kind of ostium and the area of ureter perfusion. Quantitative transformations of analyzed vessels occur first of all in fetuses of the 13th-40th week of pregnancy. Apart from main ureteral+ branches of examined organs as components of renal artery and vein, ovarian artery and vein. uterine branch of vaginal artery and vein, and umbilical artery, they have additional uretal branches, which at the end of pregnancy are reduced and do not take part in the ureter perfusion in newborn cattle. Main uretal branches occur both in fetuses and newborn cattle and they are characterized by increasing occurrence and tendency to widen perfusion range of the ureter wall. The average image of ureter arteries and veins, observed in the oldest fetuses (40th week of pregnancy) and newborn cattle, is similar to the species standard for the mature cattle as presented in other works. There are, however, different results of observations which are due to constant developmental and individual changes of the examined fetuses.