Which ions do the kidneys help regulate in the blood?

The kidneys play a crucial role in maintaining the body's homeostasis, particularly through the regulation of various ions in the blood. Among these, sodium, potassium, and calcium are essential ions that the kidneys help regulate.

Sodium is vital for maintaining blood pressure and fluid balance. The kidneys filter sodium from the blood and can reabsorb it as needed or excrete it in urine based on the body's requirements. This regulation is key for proper fluid volume and electrolyte balance.

Potassium is another critical ion regulated by the kidneys. It is essential for muscle function, including the heart. The kidneys help maintain the balance of potassium by adjusting how much is reabsorbed or excreted. High levels of potassium (hyperkalemia) can be dangerous and can result from impaired kidney function, making kidney regulation even more important.

Calcium regulation is also a significant function of the kidneys. The kidneys convert vitamin D to its active form, which is important for calcium absorption in the intestines. They also manage the excretion or reabsorption of calcium based on the body's needs, thereby playing a critical role in maintaining bone health and overall calcium levels in the blood.

The other options do contain some terms related to kidney function, but they include ions like bicarbonate