when the pH of the extracellular fluid DECLINES the

a) pH of the urine increases
b) kidneys reabsorb less water
c) kidneys excrete more sodium ions
d) kidneys secrete more potassium ions
e) kidneys excrete more bicarbonate ions

study guide question thank you

To determine the answer, we need to understand the relationship between pH and the kidneys' functioning in maintaining our body's acid-base balance.

When the pH of the extracellular fluid (ECF) declines, it means that it becomes more acidic. In response to this, the kidneys help to regulate pH by excreting excess acids and reabsorbing bicarbonate ions. Bicarbonate ions (HCO3-) act as a buffer to maintain the pH balance in the body.

Now, let's go through the options:

a) When the pH of the ECF declines (becomes more acidic), the kidneys respond by excreting more bicarbonate ions, which helps to increase the pH of the urine. So, the correct answer is **(a) pH of the urine increases**.

b) The kidneys regulate water balance through the process of reabsorption. However, changes in the extracellular fluid pH do not directly affect the kidneys' ability to reabsorb water. Thus, this option is incorrect.

c) The kidneys regulate the excretion of sodium ions to maintain the body's electrolyte balance. However, changes in the extracellular fluid pH do not directly affect the excretion of sodium ions. Therefore, this option is incorrect.

d) The kidneys regulate the secretion and excretion of potassium ions, but changes in extracellular fluid pH do not directly affect the secretion of potassium ions. Hence, this option is incorrect.

e) When the pH of the extracellular fluid declines, the kidneys respond by excreting more bicarbonate ions. Therefore, the correct answer is **(e) kidneys excrete more bicarbonate ions**.

In summary, when the pH of the extracellular fluid declines, both the pH of the urine increases and the kidneys excrete more bicarbonate ions.

the kidneys reabsorb more potassium ions.