The board of trustees is authorized to borrow funds from public or private sources under such provisions pertaining to rates of interest, repayment schedules, collateral and other requirements as may be approved by the board of trustees for the support of the guaranty student loan function of the board. The obligations so incurred by the board of trustees shall be limited to the amount of indebtedness as may be supported by revenues available from the board's guaranty student loan function and such obligations shall not constitute a debt, liability or general obligation of the state or any political subdivision thereof (other than the board of trustees), or a pledge of the faith and credit of the state or any political subdivision thereof (other than the board of trustees), but shall be payable solely as provided by the board of trustees.