Hormones are often called chemical messengers. Hormones control the body and their effects are much slower than the nervous system, but they last for longer.
There are important differences between nervous system control and hormonal control.
The pituitary gland in the brain is known as a 'master gland'. It secretes several hormones into the blood in response to the body's condition, for example blood water levels. These hormones can also act on other glands to stimulate the release of different types of hormones and bring about effects.
The body produces a range of different chemical hormones that travel in the bloodstream and affect a number of different organs and cells in the body.