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.
The thyroid and parathyroid glands are situated close to each other in the front of the neck. The thyroid gland produces the hormone thyroxine (T 4) and its more active form, T 3, which act on body cells to regulate metabolism (the chemical reactions continually occurring in the body).Some thyroid cells secrete the hormone calcitonin, which lowers calcium in the blood.hyroid and parathyroid hormones. Iodine from the diet is used to make the hormones T 4 and T 3. These hormones are produced by the thyroid gland and regulate body metabolism. Parathyroid hormone (PTH) and, to a lesser extent, calcitonin regulate levels of calcium and phosphate.