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.
The adrenal glands are two walnut-size structures that sit on top of your kidneys. Via: CLIPAREA l Custom media | Shutterstock. The Role Norepinephrine Plays In Stress. Norepinephrine, or noradrenaline, is one of several stress hormones released by the adrenal glands, two walnut-size structures that sit on top of your kidneys. Dr.