  Within the framework of Schwinger-Dyson and Bethe-Salpeter equations we
investigate the importance of pions for the quark-gluon interaction. To this
end we choose a truncation for the quark-gluon vertex that includes
intermediate pion degrees of freedom and adjust the interaction such that
unquenched lattice results for various current quark masses are reproduced. The
corresponding Bethe-Salpeter kernel is constructed from constraints by chiral
symmetry. After extrapolation to the physical point we find a considerable
contribution of the pion back reaction to the quark mass function as well as to
the chiral condensate. The quark wave function is less affected.
