1. Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan , Poland
2. Department of Anatomy, Poznan University of Medical Sciences, Poznan , Poland
3. Department of Obstetrics and Gynecology, University Hospital and Masaryk University, Brno , Czech Republic
4. Veterinary Center, Nicolaus Copernicus University in Toruń, Torun , Poland
5. Department of Toxicology, Poznan University of Medical Sciences, Poznan , Poland
6. Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, Wroclaw , Poland
7. Division of Anatomy and Histology, University of Zielona Góra, Zielona Góra , Poland