The endocrine system consists of a network of glands that release hormones to regulate various body functions.
The system controls growth, metabolism and sexual development and function. Components of this system include the endocrine pancreas, testes and ovaries, and the pituitary, adrenal, thyroid, parathyroid and pineal glands. The pituitary gland is called "the master gland" as it provides more kinds of hormones than any other gland. Pituitary hormones control the hormone release from other endocrine glands, including the thyroid, parathyroid, adrenal, ovaries, testicles and pancreas.
Once produced, hormones enter the bloodstream and most (other than prostaglandin) produce an effect elsewhere in the body. Not all cells within the body are affected by hormones, and only some cells of a particular organ may respond to a specific hormone. Some hormones control the release of other hormones.