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ALL / Clinical Sciences
Calcium homeostasis
Calcium homeostasis
Calcium ions are linked to a wide range of physiological processes. The largest store of bodily calcium is contained within the skeleton. Calcium levels are primarily controlled by parathyroid hormone, vitamin D and calcitonin.Hormonal regulation of calcium
| Hormone | Actions |
|---|---|
| Parathyroid hormone (PTH) |
|
| 1,25-dihydroxycholecalciferol (the active form of vitamin D) |
|
| Calcitonin |
|
Both growth hormone and thyroxine also play a small role in calcium metabolism.
+PassMedicine Notes
Calcium ions are linked to a wide range of physiological processes. The largest store of bodily calcium is contained within the skeleton. Calcium levels are primarily controlled by parathyroid hormone, vitamin D and calcitonin.
Hormonal regulation of calcium
Hormone_Actions| Parathyroid hormone (PTH)_- Increase calcium levels and decrease phosphate levels
- Increases bone resorption
- Immediate action on osteoblasts to increase ca2+ in extracellular fluid
- Osteoblasts produce a protein signaling molecule that activate osteoclasts which cause bone resorption
- Increases renal tubular reabsorption of calcium
- Increases synthesis of 1,25(OH)2D (active form of vitamin D) in the kidney which increases bowel absorption of Ca2+
- Decreases renal phosphate reabsorption|
- Increases plasma calcium and plasma phosphate
- Increases renal tubular reabsorption and gut absorption of calcium
- Increases osteoclastic activity
- Increases renal phosphate reabsorption in the proximal tubule|
- Secreted by C cells of thyroid
- Inhibits osteoclast activity
- Inhibits renal tubular absorption of calcium|
Both growth hormone and thyroxine also play a small role in calcium metabolism.
