  The subject of the paper is the role of the massive stellar cluster in the
activity phenomenon and in the structure of active galactic nuclei. We
introduce a simple model of stellar dynamics in the internal part of the
cluster, which allows us to include both the star-disk and the star-star
interactions. It is shown that the properties of the distribution of stars in
the vicinity of the black hole are determined both by the interaction of the
stars with the accretion disk and by the pair gravitational and contact
interaction between the stars. We calculate the distribution of stars in the
central parts of the cluster and we discuss possible effects of stellar
mass-loss due to the star-disk interaction. Finally, we study the implications
of the central cluster for active galactic nuclei activity. We model the broad
line region assuming that the gaseous wakes, following stars after each disk
crossing, play the role of the broad line region clouds, and we calculate the
corresponding line profiles. We also analyze the contribution of star-star and
star-disk collisions to active galactic nuclei variability.
