Delete Content. A plasma membrane is permeable to specific molecules that a cell needs. Transport proteins in the cell membrane allow for selective passage of specific molecules from the external environment. Each transport protein is specific to a certian molecule (indicated by matching colors).
The pancreas contains cells which release both insulin and glucagon. The endocrine system consists of a number of different glands which secrete hormones that dictate how cells and organs behave.
When the blood glucose is elevated, the pancreas secretes insulin and when the blood glucose falls, it secretes glucagons. 3) nervous system to glandâSome glands secrete hormones in direct response to the nervous system. For example, the adrenal medulla secretes a hormone in response to sympathetic nerve impulses.For information on specific endocrine glands, see the table on the following pages. All body functions are influenced by the endocrine glands; there are no processes that are NOT affected by hormone signaling.arget cells are specific to the hormone; a hormone specific to a target cell can only affect that target tissue because of the presence of receptors for the hormone on the target cells. Some endocrine glands are so complex and so specific that certain sections of the gland produce different hormones.