Tennessee Code Title 68. Health, Safety and Environmental Protection § 68-11-608

(a) The governing body of the municipality issuing bonds pursuant to this part shall prescribe and collect rentals for each medical arts building, and shall revise the rentals from time to time whenever necessary, so that the income and revenues to be derived from the rentals will always be sufficient to pay when due all bonds and interest on the bonds for the payment of which the revenues are pledged, including reserve for the bonds if any, and to provide for all expenses of operation and maintenance, of the medical arts buildings, and for an adequate depreciation account, if desired, in connection with the medical arts building.

(b) All funds arising under this part shall be kept separate and apart from other funds of the municipality.