The general treasurer, under the direction and supervision of the retirement board, shall be charged with the establishment and maintenance of such accounts and statistical records as the retirement board may require and he or she shall employ such clerical assistance as shall be necessary to carry out properly the provisions of chapters 8 — 10 of this title. The retirement board shall secure the services of an actuary who shall be the actuarial advisor of the board and who shall make the actuarial computations and valuations required by chapters 8 — 10. The retirement board shall secure the services of such physicians as shall be necessary to make the medical examinations required by those chapters. The state controller is hereby authorized and directed to draw his or her orders upon the general treasurer for the payment of such sum or sums as may from time to time be necessary, upon receipt by him or her of vouchers prepared and duly authenticated by the chief of the retirement system.