Discuss how sodium reabsorption in the proximal convoluted tubule plays a pivotal role in the reabsorption of glucose, amino acids, H2O, Cl-, and urea.

Question

aaronq · Answer

I know there are Na+/glucose and Na+/a.a.  co-trasporters in the PCT, and by reabsorbing solutes, H2O would follow these (by osmosis)... I know urea is reabsorbed in the collecting duct and secreted into the bottom of henle's loop, but how does the last part tie in with sodium reabsorption?

abb0t · Answer

Is this for metabolic biochemistry? Urea cycle produces some amino acids and also a product used to make glucose, if I remember correctly. If I fix my comp in time I'll answer better :/ with a drawing. But I think it's step 2 & 3 that tie it togethers. As far as sodium, I think it's cause glucose is the main source of energy for this sodium pct. I found the pct on Wikipedia that may have some useful info: http://en.wikipedia.org/wiki/Proximal_convoluted_tubule

aaronq · Answer

thanks for the link, dude. It's actually for a far less complicated class (animal physiology)... so from wiki

"As water leaves the lumen (via osmosis due to Na+ reabsorption), the concentration of urea increases, which facilitates diffusion in the late proximal tubule"

that pretty much sums it up, i think.

abb0t · Answer

Gotcha, yeah I need to take mammalian physio :/