Sources of Arterial Vascularization of the Polar Owl’s Kidneys
The sources of vascularization of the kidneys of five polar owl carcasses were studied by filling the vessels with self-hardening plastic Belokril through the femoral artery. High-grade oil paints were added to the monomer to give the vessels the desired color. After the injection, the carcasses were placed in a high concentration caustic soda solution for three days. The resulting corrosion impression was washed under warm water and dried. It was identified that in the lumbar trunk, the main vessel was the descending aorta, from which extra- and intraorganic arteries departed for vascularizing the kidneys. Extraorganic arteries included external and internal iliac, sciatic and middle sacral arteries. Intraorganic arteries included cranial, middle, and caudal renal arteries. Inside the parenchyma of each lobe of the kidney, intraorganic arteries branched in the main type of caudomedial, dorsomedial and lateromedial directions and were subdivided into segmental, interlobular and perilobular arteries and intralobular capillaries. An asymmetry in the branching of the renal arteries was observed. During histological examination, we noted that the renal arteries were lined with endothelium on the inner side and the intima contained endotheliocytes with oval nuclei. Under the endothelial layer were loose collagen fibers running along the middle shell. There was no loose connective tissue between the inner and middle shells, so the subendothelial layer was very weak and there was no internal elastic membrane. The muscle membrane was well developed, with collagen and elastic fibers located between the muscle fibers. The outer shell was represented by loose connective tissue with the presence of arterial and venous vessels. The collagen fibers had a slightly convoluted course.
Keywords: birds, polar owl, arteries, kidneys, parenchyma, capillaries, endotheliocytes, intima
 Ostapenko, V. A., Ermilova, A. S. and Makarova, E. A. (2017). Birds of Prey and Owls in Zoos and Nurseries: Yearbook. Raptors in zoos and breeding stations. Moscow.
 Fomenko, L. V., et al. (2019). Features of Branching of Arteries in the Organs of the Abdominal Cavity in Owl and Falcon Birds. Bulletin of Omsk SAU, vol. 2, issue 35, pp. 121-125.
 Lescheva, N. A., et al. (2019). Microecological Approaches to the Prophylactic Correction of Dysbacteriosis Microbiota in the Gastrointestinal Tract of Ducks. Presented at the International Scientific Conference the Fifth Technological Order: Prospects for the Development and Modernization of the Russian Agro-Industrial Sector (vol. 393). pp. 60-64. (TFTS 2019). Paris: Atlantis Press.
 Pervenetskaya, M. V. and Fomenko, L. V. (2018). Anatomical Features of Kidney Structure in Haysex White Hens. Journal of Pharmaceutical Sciences and Research, vol. 10, issue 10, pp. 2642-2645.
 Simons, J. R. (2013). The Blood – Vascular System Biology and Comparative Physiology of Birds. New York: Acad. Press.
 Mukhamedyarov, D. A., et al. (2019). Morphological and Functional Characteristics of the Nephrons of the Primary Bird Kidney. Morphology, vol. 12, issue 307, pp. 1381-1395.
 Islam, K. N., et al. (2004). The Anatomical Studies of the Kidneys of Rhode Island Red (RIR) and White Leghorn (WLH) Chicken during their Postnatal Stages of Growth and Development. Inter. Journal of Poultry Science J. P. Sci., vol. 3, issue 5, pp. 370- 372.
 Lucky, N. S. and Khan, M. (2010). Different Types of Oviducal Arteries in the Domestic Hen (Gallus Domesticus) in Bangladesh. International Journal of Biological Research. Int. J. Bio. Res, vol. 1, issue 1, pp. 15–18.
 Aslan, K. and Takci, I. (1998). The Arterial Vascularisation of the Organs (Stomach, Intestinum, Spleen, Kidneys, Testes and Ovarium) in the Abdominal Region of the Geese Obtained from Kars Surrounding. Caucasus University, Journal of Veterinary Medicine and Research Fac. Vet. Med. J., pp. 49-53.
 Dikich, A. A., Pervenetskaya, M. V. and Fomenko, L. V. (2019). Features of Arterial Blood Supply to the Kidneys and the Oviductal Magnum in Peking Duck. Presented at the International Scientific Conference the Fifth Technological Order Prospects for the Development and Modernization of the Russian Agro-Industrial Sector. (vol. 393). pp. 223–226. (TFTS 2019). Paris: Atlantis Press.
 Kuznetsov, S. L., Mushkabarov, N. N. and Goryachkina, V. L. (2002). Atlas on Histology, Cytology and Embryology. Moscow: Medical Information Agency.
 Petru, B., et al. (2007). The Morphology and the Surgical Importance of the Gonadal Arteries Originating from the Renal Artery. Surgical and Radiologic Anatomy. vol. 29, issue 5, pp. 367-371.
 Batach, A. L. (2012). Morphological and Histological Study for the Kidneys of Coot Bird (Fulica Atra). Basrah journal of veterinary research Bas. J. Vet. Res., vol. 25, pp. 128-136.
 Borkivets, D. S. (2015). Morphology and Vascularization of the Kidneys in Chickens of the Cross “Sibiryak - 2” in Postnatal Ontogenesis. Омский научный вестник, № 1 (128). Omsk, p. 16