Final answer:
The bicarbonate buffer system in the body is primarily controlled through the renal system.
Step-by-step explanation:
The bicarbonate buffer system in the body plays a crucial role in maintaining acid-base balance and pH. Bicarbonate ion concentrations in the blood are primarily controlled through the renal system. The kidneys conserve and pass back bicarbonate ions into the blood, helping to regulate and buffer changes that would make the blood more acidic.