A cooling structure of a heat-generating electronic component including a cooling circuit, which includes a cooling fluid delivery unit, a first heat exchanger for absorbing and discharging thermal energy at the heat-generating electronic component as well as a control structure. The control structure adjusts the cooling fluid flow and thus the cooling capacity of the heat exchanger to such value that at a predetermined temperature in the area of the electronic component a balance is brought about between the heat quantity generated and the heat quantity discharged. The cooling structure is inserted in the deflecting forming a bendable adapter outside the end cap of an endoscope.