The parathyroids produce a hormone called parathyroid hormone (PTH). PTHPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.THPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.
DN = Diameter Nominal. The term Diameter Nominal refers to the internal diameter of a pipe. Together with the nominal pressure rating and the materials class, all dimensions of a piping line, e. g. flange dimensions, are defined by indicating the nominal diameter. Steel is often not specified, but assumed as material.
W = nominal outside diameter of coupling, in., and. d1 = diameter at the root of the coupling thread in the power tight position, in. This dimension is based on data given in API Spec. 5B, Threading, Gauging, and Thread Inspection of Casing, Tubing, and Line Pipe Threads, and other thread geometry data. The coupling internal yield pressure is typically greater than the pipe body internal yield pressure.