Tenn. Code Ann. § 8-34-201: Establishment of system

(a) A retirement system is established and placed under the management of the board of trustees, for the purpose of providing retirement allowances and other benefits under chapters 34-37 of this title. The retirement system so created shall be established as of July 1, 1972.

(b) The retirement system is established as a qualified defined benefit plan under chapters 34-37 of this title, as amended, pursuant to §§ 401(a) and 414(d) of the Internal Revenue Code ( 26 U.S.C. §§ 401(a) and 414(d) ), or such other provision of the Internal Revenue Code as applicable, and applicable United States department of the treasury regulations and other guidance.