comparing solutes in the plasma, nephron and urine

[lab cat]

is it correct to say that veins carry blood with high concentrations of waste prducts and arteries carry blood with high concentrations of nutrients?

[Poison]

Not always(think about pulmonary artery and vein. ), but generally right.

[canalon]

And think about the portal vein (not sure of the english name, the vein that commes along the bowels)

[Poison]

As much as I know, the name is the same.

[sdekivit]

and what about the umbilical veins ?