AC-19691 - calcium-oxide-96-extra-pure | 1305-78-8

Calcium is a chemical element with the symbol Ca and atomic number 20. It has an atomic weight of 40.078, which means that it is 40.078 times heavier than hydrogen. Calcium is an alkaline earth metal, as are magnesium and barium. Calcium is classified as a hard metal because it has a high melting point and its oxide layer resists corrosion by water and air. The ionized form of calcium (Ca2+) may be found in the cytosol, or in transport vesicles in muscle cells or other types of cells such as those of the intestine or bone cells. The main biological role of calcium ions is to maintain the potential difference across excitable cell membranes, enabling normal nerve transmission and muscle contraction, including the contraction of heart muscles. The concentration of calcium ions in extracellular fluid is tightly regulated by the kidneys under instruction from parathyroid hormone (PTH) and calcitonin hormones to keep blood calcium levels within a narrow range