Chapter 18. The URINARY SYSTEM. 4 FUNCTIONS OF THE URINARY SYSTEM. Regulating blood volume and blood pressure Regulating plasma concentrations of ions Helping stabilize blood pH Conserving valuable nutrients. THE ORGANIZATION OF THE US. Kidneys : produce urine
The URINARY SYSTEM
Electrolyte balance is important because total electrolyte concentrations affect water balance.
H2CO3/HCO3− : the most important factor affecting pH of ECF
CO2+ H2O H2CO3 H2CO3 H+ + HCO3−
CO2 + H2O↔ H2CO3 ↔ H+ + HCO3−
CO2 + H2O ↔ H++ HCO3−
PO43− : primary affecter of ICF pH. Technically also plays a role in ECF, but only supporting, since ICF pH is dominated by H2CO3/HCO3−. Really, this is the dihydrogen phosphate buffer system.
If pH goes up, carboxyl group (– COOH) releases a H+.
If pH goes down, an amino group (– NH2) takes a H+ for –NH3+.