The effects of stimulated Raman scattering and stimulated Brillouin scattering in transparent spherical particles are theoretically described. The set of equations for the amplitude coefficients of fields of the incident and Stokes waves is derived and studied. The threshold ratio is obtained for transition from spontaneous scattering to stimulated Raman scattering. The spatial structure of interacting natural oscillational modes of a particle is shown to affect significantly the value of this threshold. It is found that the higher is the Q-factor of resonance modes, the more strongly it is affected by particle surface deformations, which may be spontaneous or connected with the effect of ponderomotive forces in a light field.