Sodium is ant for fluid balance, not just inside the cells, but peeing out. In the proxima convoluted tuble sodium is thrown out of the cell because of the sodim potassium pump. If you eat adequate amounts of glucose, all of it is reabsorbed back into your blood stream. This is why, if you eat too much, obviously it goes out in the p so that's the importance of the pump there. A little bit further down, it's pulling in not just glucose, but amenal acids as well. And if sodium goes in, it can also throw out hydrogen irons. So again, we're selectively now pulling in nutrient and excreting