The renal threshold is the
A)maximum amount of a particular substance that can be excreted in the urine per unit of time
B)maximum amount of a particular substance that the tubular cells are capable of actively reabsorbing per unit of time
C)plasma concentration of a particular substance at which its Tm is reached and the substance first appears in the urine
D)maximum amount of waste products that can be concentrated in the urine per unit of time
E)maximum amount of water that can be osmotically absorbed across the tubules per unit of time

Question

Quizplus · Accepted Answer

The renal threshold is the plasma concentration of a particular substance at which its tubular maximum (Tm) is reached and the substance begins to appear in the urine. It is the point at which the transporters responsible for the reabsorption of that substance become saturated, and any excess is excreted in the urine. This threshold varies depending on the substance, and is an important factor in diagnosing certain conditions such as diabetes.

The Renal Threshold Is the