A girl who is about to give a speech in front of her class gets nervous her palms are sweaty, her heartbeat and breathing quicken, and she feels jittery. A body builder takes drugs that help make his muscles grow bigger. A man who has diabetes loses weight, and he feels queasy and exhausted. We all need hormones for our bodies to function properly. Hormones help us process energy, respond to changes in our environment, reproduce, maintain the right balance of nutrients, and perform many other vital functions.
Hormones are chemicals produced by specialized organs called glands.
Several glands are pictured here, with descriptions of the hormones they make. Once a hormone is released by a gland, it travels through the body in the blood, in search of a target. A target organ must have special receptors that recognize and bind to the hormone. This interaction allows hormones to have specific effects in the appropriate areas of the body. You can place your pointer on any colored gland or organ in the picture above to learn more.