PHGY 210 Lecture Notes - Lecture 2: Parathyroid Hormone Receptor, Calcitriol Receptor, Bone Resorption
3 Feb 2018
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Document Summary
Calcium ion plays a key role in many fundamental biological processes. Inadequate vitamin d will cause disease with inadequate calcification of skeleton. Lack of calcification may cause distortion in bones. With na+ and k+ helps maintain transmembrane potential of cells. Important in release of hormones and neurotransmitters. Concentration in cellular and extracellular fluid ~10mg/100ml (concentration in blood). Most importantly, the body has to ensure there is sufficient amount of calcium in the circulation by maintaining the calcium level in circulation in a very narrow range. In circulation 50% free, 50% bound to albumin. About 99% of the body"s calcium is in bone, and part of this calcium is quite loosely bound. Without sufficient calcium, the cells may die. In mice model, mice with insufficient calcium will decalcify their own bones to maintain normal levels of calcium in circulation. Maintenance of plasma calcium is achieved mainly by exchange between bone and plasma under influence of hormones.
