Solute Flow through Kidneys

Solute	Typical Direction	Typical Mechanism
Na+	To blood	Active transport Cotransport
Nutrients	To blood	Cotransport Active transport
H2O	To blood	Osmosis
HCO3-	To blood	Counter-transport with Cl-
Cl-, K+, Ca 2+, Mg 2+	Depends on need	Varies K+: often counter-transport with Na+
H+	To urine	Counter-transport with Na+
Urea	To urine	Diffusion