A rotor blade includes a mounting portion comprising a mounting body that is formed to receive a coolant therein. An airfoil portion extends substantially radially outwardly from the mounting body and includes an airfoil body. The mounting body and the airfoil body define a plurality of primary cooling passages that extend substantially radially therein for routing the coolant through the airfoil body. Each of the primary cooling passages includes a cooling flow outlet that is formed along a tip portion of the airfoil body. The airfoil body further defines a plurality of trailing edge cooling passages, each having a coolant outlet that is formed along a trailing edge portion of the airfoil body. At least a portion of the trailing edge cooling passages are formed along a radially outer portion of the trailing edge proximate to the tip portion of the airfoil body.