Byrka H. Morphofunctional peculiarities of Meckel's diverticulum in geese of big grey breed.

The thesis devotes to the investigations of morphofunctional peculiarities of Meckel's diverticulum in geese of big grey breed at ontogeny. It has been determined, the vitelline duct of geese fetus as an embryo of Meckel's diverticulum fulfils trophic, bloodforming and immune functions on the 27 day of incubation. After gosling hatching it transforms into Meckel's diverticulum which is situated on the antimesenterial surface of the loop of the jejunum. The increase of Meckel's diverticulum occurs till three months old age of geese, about what indicate the maximum meanings of length indices (17,50±3,50 mm), the area of transversal section (13,84±0,90 mm2) and the wall (12,63±0,82 mm2). These indices reduce with geese age increasing. The wall of Meckel's diverticulum is formed by mucous, muscular and serous membranes. The most developed membrane is the mucous one (51,43-92,08 % from the wall area). The epithelium of one-day-old goslings is monostratal cubic bordening, and the epithelium of three-days-old goslings is monostratal prismatic bordening. The crypta area reaches the maximum meaning in two-months-old geese (39,66 %). In the six-months-old geese at the crypta place are generated the oseoid formation. Morphofunctional maturity of Meckel's diverticulum comes at the 21 days old age. The content of diffuse lymphoid tissue with antenodes and lymphoid nodes changes after approach of morphofunctional maturity. The maximum area of lymphoid tissue is in the wall of Meckel's diverticulum in three- months-old geese (83,77 %). In the lymphoid tissue of Meckel's diverticulum wall has been determined the content, distribution and quantative ratio of lymphocytes with clusters of differentiation CD4+, CD8+ and CD45RА+.