The human body fluids contain common electrolytes, both cations such as na⁺ and k⁺, and anions such as cl⁻ and (hco₃)⁻. each electrolyte has unique functions in the body in addition to its general function of contributing to the exertion of osmotic pressure. to carry out these functions effectively, each electrolyte must be maintained within a hydrostatic concentration range in the blood plasma. regulating normal concentration of the different electrolytes in the blood plasma requires input to be greater than output.