Hypothalamus

The hypothalamus is an organ about the size of a lump of sugar. It lies at the base of the brain, known as the cerebral cortex. Although it is part of the brain, the hypothalamus is considered part of the endocrine system because it secretes several hormones.

The hypothalamus regulates:

the ebb and flow of body fluids
metabolism
blood sugar levels
body temperature
body rhythms (activity and rest, appetite and digestion, sexual desire, menstrual and reproductive cycles)
activities of the nervous system and the endocrine system in three ways:
- controls the endocrine cells of the adrenal interior (medullae), causing them to release hormones into the bloodstream
- acts as an endocrine organ by releasing ADH and oxytocin into the posterior pituitary
- secretes two classes of regulatory hormones:
  - releasing hormones (RH) which stimulate the production of one or more hormones in the anterior pituitary
  - inhibiting hormones (IH) which prevent the synthesis and secretion of pituitary hormones.

This page was updated in November 2005.