Chapter 6 introduced an essential part of the cell: the. plasma membrane. Thanks to the selective permeability of. phospholipid bilayers and the activity of membrane trans-. port proteins, this structure creates an internal environment. that is different from conditions outside the cell. Our task.
When calcium levels decrease, this stimulates the parathyroid gland to release parathyroid hormone. Parathyroid hormone encourages the normal process of bone breakdown (essential for maintenance and growth of the bone). This process of bone breakdown releases calcium into the bloodstream.
Description. Parathyroid hormone (PTH) is produced by the 4 parathyroid glands, which reside behind the thyroid gland in the anterior neck. The release of PTH is normally stimulated by low calcium levels in the body.PTH release results in a signal to the bones to release calcium into the bloodstream and also to the kidneys to resorb calcium in the collecting system and excrete phosphorus.he release of PTH is normally stimulated by low calcium levels in the body. PTH release results in a signal to the bones to release calcium into the bloodstream and also to the kidneys to resorb calcium in the collecting system and excrete phosphorus.