Time-resolved measurements of the nuclear volume response of human peripheral T-lymphocytes, under aniosmotic conditions, are presented. In the experiments slit scanning FlowCytometry methods were used. We propose an extension to the standard solid viscoelastic model to interpret the observed dynamical behavior of the nucleus. It is shown that experimental and theoretical evidence indicates a passive nuclear response merely induced by a mechanical link (i.e., the cytoskeleton) between the cell membrane and the nuclear envelope. Implications of this work to the field of cellular mechanics and cytoskeletal rheology are surveyed.