What is the endocrine system?



The endocrine system is a set of body organs that secrete
hormones into the bloodstream. Carried to every part of the body,
these hormones control many body functions. Organs included in the
endocrine system include the testes and ovaries, the pituitary, the
thyroid, and the pancreas and adrenal glands.

Hormones secreted by some endocrine glands control other
endocrine glands. For example, the pituitary gland in the brain
secretes the hormones FSH and LH.(1) In the male, they cause the
testes to make the hormone testosterone. The pituitary gland
monitors the amount of testosterone produced by the testes.(1) If
the level of testosterone is high, the pituitary gland secretes
less FSH and LH. This signals the testes to stop producing
testosterone. If the testosterone level is low, the pituitary
secretes more FSH and LH. This causes the testes to produce more
testosterone. This is one example of how a feedback mechanism is
used by the body to control many body functions.