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.
What are the parathyroid glands, and what do they do? The parathyroid glands are four tiny glands, located in the neck, that control the body's calcium levels. Each gland is about the size of a grain of rice (weighs approximately 30 milligrams and is 3-4 millimeters in diameter). The parathyroids produce a hormone called parathyroid hormone (PTH).