The ultrastructure of Drosophila heart cells

► The ultrastructural analysis of the Drosophila heart revealed a complex architecture. ► Ostial cells differentiate at the end of embryogenesis forming hemolymph inflow tracts. ► Intracardiac valve cells are enlarged and show cellular cytoplasmic free cavities. ► Alary syncytial muscles are connected to the heart tube by ECM fibers. ► Ventral syncytial muscles delineate the adult heart toward the body cavity.