IGCSE Human Biology Help:Watch this thread
Sodium ions: 23
My homework is asking me to state two advantages based of the data above, searched on google, nothing, I know protein is too large to pass the membrane and the dialysis maintains the concentration of urea but other than that can't think of anything :/
If the sodium levels are above 17 some will diffuse across to the plasma fluid. Too high levels of sodium is bad for you so if your kidney's can't remove it than it needs to be removed by the plasma fluid. So, having the sodium concentration at 17 is an advantage because it ensures the right concentrations of sodium are in the blood.
Having the same concentration of Glucose means none will diffuse across the membrane so this is not effected.
As protein is too large to pass the membrane, it will not be effected by the dialysis fluid, even though there is a concentration gradient. You need protein in you anyway, so, as it can't diffuse across, they do not need to put any protein in the dialysis fluid.
I could be wrong but I do think that urea is removed from the body as well. The concentration of this in the dialysis fluid is 0 to make lots of the urea diffuse across. For example, the URR stands for the Urea Reduction Ratio which is used by hospitals to see how effective the dialysis is, by comparing the concentration of urea before and after dialysis.