Calcium metabolism

Article By:

Putney, James W. National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.103100

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• Calcium metabolism, published June 2014:Download PDF Get Adobe Acrobat Reader

The use and maintenance of calcium levels in the body. Calcium metabolism is the sum of the biochemical and physiological processes involved in maintaining the concentration of calcium in plasma (the fluid portion of blood or lymph) at a constant level and providing a sufficient supply of calcium for bone mineralization (Fig. 1). In general, calcium is essential to all forms of life. It plays fundamental roles in cell biology and signaling, in the functioning of organs and organ systems, and in the functioning of organisms. In the most complex organisms, that is, vertebrates, calcium is a key ingredient in the skeleton. In vertebrates, about 99% of total body calcium is found in bones, specifically in the form of a crystalline structure called hydroxyapatite (also spelled as hydroxylapatite). This calcium not only forms the basis of skeletal rigidity and structure, but also serves as a reservoir for calcium that can be mobilized to the blood in response to specific environmental or endocrine signals. When excessive resorption of bone occurs due to inadequate calcium or vitamin D in the diet, diseases result, and the symptoms of these diseases may include misshapen skeletal structure and bones that break easily. See also: Bone; Calcium; Metabolism; Skeletal system; Vitamin D

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