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.
Thyrotropin (TSH) (3-5%) 30,000 Stimulates thyroid cells to trap iodide and to synthesize and secrete thyroid hormones. Luteinizing Hormone (LH) (5-10%) 30,000 Stimulates cells of the theca interna, corpus luteum, and the Leydig cells to synthesize sex steroid hormones.