We find classical open string solutions in the AdS_5\times S^5/\Zop_2
orientifold with angular momenta along the five-sphere. The energy of these
solutions has an expansion in integral powers of λ with sigma-model
corrections suppressed by inverse powers of J - the total angular momentum.
This gives a prediction for the exact anomalous dimensions of operators in the
large N limit of an N=2Sp(N) Super-Yang-Mills theory with matter.
We also find a simple map between open and closed string solutions. This gives
a prediction for an all-loop planar relationship between the anomalous
dimensions of single-trace and two-quark operators in the dual gauge theory