In administering the EMS system, the local EMS agency, with the approval of its medical director, may designate and contract with hospitals or other entities approved by the medical director of the local EMS agency pursuant to Section 1798.105 to provide medical direction of prehospital emergency medical care personnel, within its area of jurisdiction, as either base hospitals or alternative base stations, respectively. Hospitals or other entities so designated and contracted with as base hospitals or alternative base stations shall provide medical direction of prehospital emergency medical care provided for the area defined by the local EMS agency in accordance with policies and procedures established by the local EMS agency and approved by the medical director of the local EMS agency pursuant to Sections 1797.220 and 1798.