And what that means is that substance, because it is filtered and not reabsorbed, it will end up being in the urine that is released by the body. Now the second method is the following. It is not filtered through our glomerilus, but as it travels through the Ethernet arterial and eventually ends up in the periobular capillaries, it can be secreted by those capillaries into the tubules and then it ends up in our urine. So these are the only two ways by which some given substance can end up in the filtrate and ultimately released in our urine. Now, as I mentioned earlier, different substances have different values for the renal clearance. So let's begin by supposing we have some hypothetical substance.