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.
The pitch diameter (often called the effective diameter) of a parallel thread is the diameter of the imaginary co-axial cylinder which intersects the surface of the thread in such a manner that the intercept on a generator of the cylinder, between the points where it meets the opposite flanks of a thread groove, is equal to half the nominal pitch of the thread.