Renal Quiz 4: Role of the Kidney in Calcium, Phosphate, K+ Homeostasis

Flashcards based on the lecture notes covering the role of kidneys in calcium and phosphate homeostasis, including hormone regulation, nephron function, and implications in chronic kidney disease.

What is the primary function of the kidney in calcium and phosphate homeostasis?

The kidney regulates extracellular calcium and phosphate levels, primarily by reabsorbing filtered calcium and phosphate.

How much of the filtered calcium is reabsorbed by the kidney?

About 99% of filtered calcium is reabsorbed by the kidney.

What hormone primarily regulates calcium reabsorption in the kidney?

Parathyroid hormone (PTH) primarily regulates calcium reabsorption.

Where in the nephron is most phosphate reabsorption occurring?

Most phosphate reabsorption occurs in the proximal tubule.

What effect does parathyroid hormone have on phosphate reabsorption?

Parathyroid hormone inhibits phosphate reabsorption, leading to increased phosphate excretion.

Why are patients with calcium forming kidney stones treated with thiazide diuretics?

Thiazide diuretics reduce calcium concentration in the distal tubule, decreasing the likelihood of calcium precipitating and forming stones.

What are some important functions of calcium in the body?

Calcium is crucial for bone and tooth structure, muscle function, nerve transmission, and cellular signaling.

What occurs in chronic kidney disease regarding calcium phosphate homeostasis?

In chronic kidney disease, there is secondary hyperparathyroidism and decreased calcitriol formation, leading to disturbances in mineral metabolism.

How does the kidney influence plasma calcium levels?

The kidney influences plasma calcium levels by modulating renal calcium excretion through PTH and calcitonin.

What is the effect of hypercalcemia on potassium handling in the kidney?

Hypercalcemia is treated with diuretics like furosemide, which inhibit calcium reabsorption, thus aiding in calcium excretion.