F.G. Sitdikov - Dr.Sc. (Biol.), Professor, Department of Anatomy, Physiology and Human Health, Kazan (Volga Region) Federal University (Kazan). E-mail: fgsitdikov@mail.ru A.R. Gissatullin - Ph.D. (Biol), Associate Professor, Department of Anatomy, Physiology and Human Health, Kazan (Volga Region) Federal University (Kazan). E-mail: almaz-giz@rambler.ru R.R. Minnachmetov - Ph.D. (Biol), Associate Professor, Department of Anatomy, Physiology and Human Health, Kazan (Volga Region) Federal University (Kazan). E-mail: Minnakhmetov@mail.ru G.A. Bilalova - Ph.D. (Biol), Associate Professor, Department of Anatomy, Physiology and Human Health, Kazan (Volga Region) Federal University (Kazan). E-mail: g.bilalova@mai.ru N.B. Dikopolskaya - Ph.D. (Biol), Associate Professor, Department of Anatomy, Physiology and Human Health, Kazan (Volga Region) Federal University (Kazan). E-mail: bettydn@mail.ru