The endocrine system is made up of glands. A gland secretes chemicals called hormones directly into the bloodstream. The blood carries each hormone around the body to a target organ, where it produces an effect.
Compared with the nervous system, the effects of hormones are slower, because the chemical has to travel in the blood. But they act for longer, because a hormone stays active after the message has arrived.
The pituitary gland in the brain is called the master gland. It secretes several hormones into the blood in response to conditions in the body. These hormones act on other glands and make them release their own hormones, which bring about the effects.
You should know where the main glands are: the pituitary gland in the brain, the thyroid in the neck, the adrenal glands above the kidneys, the pancreas below the stomach, the ovaries in the lower abdomen of a woman, and the testes in a man.
