  The nuclear response functions for high energy electron scattering were
calculated in the wide region of excitation energy. The three typical regions
were studied: the quasi-elastic region, the $\Delta$-excitation region and the
intermediate region where the meson-exchange currents give significant
contribution. In the quasi-elastic and the $\Delta$ regions the response
functions were found for finite size nucleus with account of relativistic
kinematics. The contribution of the meson-exchange currents was calculated in
the relativistic Fermi-gas model. The results were compared with the electron
scattering data at high momentum transfer from $^{12}C$ and $^{16}O$.
