Adrenal glands, also known as suprarenal glands, are small, triangular-shaped glands located on top of both kidneys. These glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress, and other essential functions. They are composed of two parts — the cortex and the medulla — which are each responsible for producing different hormones. When adrenal glands don’t produce enough hormones, this can lead to adrenal insufficiency. The role of the adrenal glands in your body is to release certain hormones directly into the bloodstream. Many of these hormones have to do with how the body responds to stress, and some are vital to existence. Both parts of the adrenal glands — the adrenal cortex and the adrenal medulla — perform distinct and separate functions.

Source: Johns Hopkins Medicine