Calcium
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Calcium is a chemical element, having the chemical symbol Ca. Its atomic number (the number of protons) is 20. It has a standard atomic weight of 40.078 g•mol −1, and is a solid in its elemental form.
Calcium is considered to be a member of the "alkaline earth metal" class of element. At a pressure of 101.325 kPa, it has a boiling point of 1,484 °C, and a melting point of 842 °C.
Calcium is essential for life, particularly in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes, including neuromuscular contractions. It is also a major material used in mineralization of bones, teeth and shells.
Drug toxicity
Calcium may increase the rate of myocardial infarctions according to a meta-analysis[1] and a more recently analyzed randomized controlled trial.[2]
References
- ↑ Bolland MJ, Avenell A, Baron JA, Grey A, MacLennan GS, Gamble GD et al. (2010). "Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis.". BMJ 341: c3691. DOI:10.1136/bmj.c3691. PMID 20671013. PMC PMC2912459. Research Blogging. Review in: Ann Intern Med. 2010 Nov 16;153(10):JC5-7 Review in: Evid Based Med. 2010 Dec;15(6):181
- ↑ Bolland MJ, Grey A, Avenell A, Gamble GD, Reid IR (2011). "Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women's Health Initiative limited access dataset and meta-analysis.". BMJ 342: d2040. DOI:10.1136/bmj.d2040. PMID 21505219. PMC PMC3079822. Research Blogging. Review in: Ann Intern Med. 2011 Aug 16;155(4):JC2-3 Review in: Evid Based Med. 2012 Feb;17(1):16-7