Calcium balance and fluxes in a normal human Calcium balance and fluxes in a normal human. Solid arrows depict a direct effect, whereas dashed arrows depict an indirect effect. The thickness of the arrows is representative of the magnitude of the flux. ECF = extracellular fluid; PTH = parathyroid hormone; VIT. = vitamin. (Reproduced with permission from Bruder J, et al. Mineral metabolism. In: Felig P, Frohman L, eds. Endocrinology and Metabolism. New York: McGraw-Hill Publishers, Inc; 2001:1081. Copyright © The McGraw-Hill Companies, Inc.) Source: Thyroid, Parathyroid, and Adrenal, Schwartz's Principles of Surgery, 10e Citation: Brunicardi F, Andersen DK, Billiar TR, Dunn DL, Hunter JG, Matthews JB, Pollock RE. Schwartz's Principles of Surgery, 10e; 2014 Available at: http://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/books/980/bru_ch38_f027.png&sec=100403290&BookID=980&ChapterSecID=59610880&imagename= Accessed: November 10, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved