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.
CCK stimulating vagus nerve. CCK stimulate vagus nerve to send signals to hypothalamus-cells in hypothalamus release a neurotransmitter that is the shorter version of CCK --CCK in intestines cannot cross the blood-brain barrier-but it can stimulate cells in hypothalamus to release cells almost like itself. î î î.