  We study the chiral phase transition at finite $T$ and $\mu_B$ within the
framework of the SU(3) Nambu-Jona-Lasinio (NJL) model. The QCD critical end
point (CEP) and the critical line at finite temperature and baryonic chemical
potential are investigated: the study of physical quantities, such as the
baryon number susceptibility near the CEP, will provide complementary
information concerning the order of the phase transition. We also analyze the
information provided by the study of the critical exponents around the CEP.
