Final answer:
The kidneys regulate a rising blood pH by excreting hydrogen ions and reabsorbing bicarbonate ions, which helps in balancing acid-base levels in the body. option D.
Step-by-step explanation:
The kidneys help maintain a rising blood pH by excreting hydrogen ions and reabsorbing bicarbonate ions by the tubule cells. The correct answer to the question is: D) hydrogen; bicarbonate.
This process aids in regulating the acid-base balance in the body. When the blood pH starts to rise, indicating that the blood is becoming too alkaline, the kidneys reabsorb more bicarbonate ions from the urine, which acts as a buffer to moderate pH levels.
Meanwhile, the secretion of hydrogen ions into the urine helps to remove excess acidity, facilitating the maintenance of homeostasis of mineral ions in the extracellular fluid.
Specifically, this process takes place in the renal tubules where sodium ions are reabsorbed and hydrogen ions are excreted. Additionally, intercalated cells in the collecting ducts have proton pumps that actively secrete hydrogen ions into the urine, contributing further to the regulation of blood pH. Option D.