Constituent Quark and Hadronic Structure in the Next-to-Leading Order

The structure of a dressed quark is utilized to evaluate the structure function of proton and pion. It is found that there is a simple relationship between $F_2^p$ and $F_2^{\pi }$. The ambiguity in the normalization of $F_2^{\pi }$ is discussed. Furthermore, the polarization structure function of the constituent (dressed) quark is calculated in the leading order. While, it does produce all the available data on polarized hadronic structure, it requires a significant contribution to the proton spin from the orbital angular momentum.