Abstract : We investigate the role played by the Polyakov loop in the dynamics of the chiral phase transition in the framework of the so-called PNJL model in the SU(2) sector. The results are compared with those of the NJL model. We present the phase diagram in terms of the chemical potential and temperature. The inclusion of the Polyakov loop moves the critical points to higher temperatures. The critical properties of physical observables, such as the baryon number susceptibility and the specific heat, are analyzed in the vicinity of the critical end point, with special focus on their critical exponents.