In this work, such concepts as gravitational cells and gravitational strings were successfully built into the theory of the gravitational field. This innovation made it possible to move from general ideas about gravitational interaction to a deeper and more detailed understanding of this physical process and to obtain significant scientific results. These results include: obtaining the formula for the gravitational constant, the mass of an electron and the mass of a hydrogen atom through fundamental physical constants; determining the energy of a graviton, obtaining the length and frequency of gravitational waves; obtaining the distance of action of gravitational forces; obtaining a relativistic formula for the speed of a body in a gravitational field, and etc. In this work, Planck's constant was successfully applied to the theory of gravitational cells and strings. As a result, the formula for the minimum distance of gravitational interaction, the formula for the mass of an electron, and the formula for the mass of a hydrogen atom were obtained. Through the synthesis of the theory of gravitational cells and the relativistic formula of Einstein's total energy, the relativistic formula for the velocity of a body in a gravitational field was obtained. The results obtained by the new formulas completely coincided with the known scientific and experimental data. A distinctive feature of this study is the fact that only fundamental physical constants are present in the new formulas.