The developmental features of leaflets of atrio-ventricular valves.

The purpose of the study was to determine the features of structure and development of atrio-ventricular valves using the macro-micriscopic, histological and immunohystochemical methods (marker CD 34). The leaflets of the atrio-ventricular valves of 96 hearts of embryos, fetus and people of different age were used. It was determined that the primary valvular vehicle of heart starts to develop at the 7th week of prenatal ontogenesis. The mesenchyme of endocardial cushions and superior part of delamination plate of atrio-ventricular canal take part in the development of the leaflets of atrio-ventricular valves. The inferior part of delamination plate participates in the primary filaments of tendons of valvular vehicle and apex of the papillary muscle of ventricle. The onset of development of the structures participating in the fibrous ring takes place in the same time in the superior parts of delamination plate. The immunohystochemical study of leaflets of atrio-ventricular valves showed the maximal CD 34 level in the base of leaflets in hearts of all groups.