The administrative director shall appoint a medical director who shall possess a physician’s and surgeon’s certificate granted under Chapter 5 (commencing with Section 2000) of Division 2 of the Business and Professions Code. The medical director shall employ medical assistants who shall also possess physicians’ and surgeons’ certificates and other staff necessary to the performance of his or her duties. The salaries for the medical director and his or her assistants shall be fixed by the Department of Human Resources, commensurate with the salaries paid by private industry to medical directors and assistant medical directors.