Question

5. Explain how the plasma concentration of free Ca2+ concentration is regulated and include the function of inorganic phosphate (HPO42-) in this process.

Please give a detailed answer. Add supportive equation if possible.

Answer 1

• Plasma concentration of free calcium (plasma calcium homeostasis) is regulated by the action of 2 hormones namely,
  • Parathyroid hormone (PTH)
  • Calcitonine
• calcium ions are absorbed from the small intestine to the body.
• And excess amount of calcium are excreted through the kidneys.
• Storage of calcium is in the bones.
• Parathyroid hormone (PTH) have important role on the regulation of plasma concentration of calcium.
• Parathyroid hormone secreted from parathyroid gland
• And released during the low level of calcium in plasma.
• Parathyroid hormone increases the calcium level by different methods.
• Parathyroid hormone act on bone cells (Osteoclasts) to release the stored calcium from bones to the blood stream.
• Parathyroid hormone increases blood calcium level by enhancing the formation of calcitriole which increases the absorption of dietary calcium from intestine and also the reabsorption of calcium from kidneys.
• calcitonin is a hormone produced by thyroid gland.
• CalcCalcitonin act opposite to the parathyroid hormone
• Calcitonin inhibits the osteoclasts and stimulate osteoblast to store the calcium. And also the calcitonin enhances the kidney to excrete calcium through the urine in increased calcium conditions.
• Function of inorganic phosphate in calcium regulation.
• Phosphate level effects the calcium level in blood.
• Calcium and phosphate are acting oppositely.
• If the calcium level of blood decreased then the phosphate level increased and vice versa.
• So during checking calcium level phosphate level also monitored.