Rock is considered an ecosystem because based on the definition of ecosystem. A rock is happens to be in our environment which makes it part of our ecosystem. 1 person found this useful.
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). PTHPTH - parathyroid hormone raises the blood calcium level by: breaking down the bone (where most of the body's calcium is stored) and causing calcium release. increasing the body's ability to absorb calcium from food.
PTH2 : Parathyroid hormone (PTH) is produced and secreted by the parathyroid glands, which are located along the posterior aspect of the thyroid gland. The hormone is synthesized as a 115-amino acid precursor (pre-pro-PTH), cleaved to pro-PTH and then to the 84-amino acid molecule, PTH (numbering, by universal convention, starting at the amino-terminus).