Put simply, volume refers to the number of contracts traded. For any trade to occur, the market needs to produce a buyer and a seller. A transaction occurs when buyers and sellers meet and is referred to as the market price.
This hormone is secreted from cells of the parathyroid glands and finds its major target cells in bone and kidney. Another hormone, parathyroid hormone-related protein, binds to the same receptor as parathyroid hormone and has major effects on development.
Although the parathyroid glands are located next to (and sometimes inside) the thyroid gland, they have no related function. The thyroid gland regulates the body's metabolism and has no effect on calcium levels while parathyroid glands regulate calcium levels and have no effect on metabolism.