Calcium (Ca++) The total amount of calcium circulating in the blood is small (9.0-10.5 mg/dl) and half of the total amount is bound to albumin a plasma protein. In humans, calcium ranks fifth after oxygen, carbon, hydrogen, and nitrogen. Intracellular calcium is located primarily in the mitochondria. Approximately 99% of calcium is contained in bones and teeth as calcium hydroxyapatite an inorganic compound that contributes to bone rigidity (McCance, K. L., & Huether, S. E. 2013). Calcium regulation is critical for normal cell function, neural transmission, membrane stability, bone structure, and intracellular signaling. Calcium is required for the normal blood clotting by activating the release of thromboplastin from the blood platelets. Approximately 40% of calcium is in the ionized form. Ionized …show more content…
Oral magnesium salts can be used to supplement magnesium, but they are generally not well absorbed from the gastrointestinal tract. Magnesium supplements can be beneficial. Improvements in myocardial metabolism, cardiac output, and vascular smooth muscle tone are positive outcomes. Cardiac arrhythmias can be reduced while lipid and glucose metabolism are improved. Hypermagnesemia Hypermagnesemia is a serum concentration greater than 2.5 mEq/L. This is rare occurrence and is usually caused by renal failure as the kidney has a large capacity for magnesium excretion. The renal system is capable of nearly 100% fractional excretion when renal magnesium threshold is exceeded. Clinically significant hypermagnesemia is uncommon in patients with normal renal function. Excessive magnesium intake and magnesium containing antacids can increase levels as well. Clinical Manifestations Signs and Symptoms Signs and symptoms include nausea, vomiting, cutaneous flushing, and muscle