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.
Parathyroid chief cell. Parathyroid chief cells (also called parathyroid principal cells or simply parathyroid cells) are cells in the parathyroid glands which produce parathyroid hormone. The end result of increased secretion by the chief cells of a parathyroid gland is an increase in the serum level of Calcium. Parathyroid chief cells constitute one of the few cell types of the body that regulate intracellular calcium levels as a consequence of extracellular (or serum) changes in calcium concentration.