The hypothalamus is a brain part at the base of the brain. It connects the endocrine system to the nervous system. The word hypothalamus is a Greek word which means "under the thalamus"; it is used because hypothalamus is below the thalamus, and above the brain stem.
The hypothalamus controls body temperature, hunger, thirst and circadian cycles.It is the control system which regulates the pituitary gland, the 'master gland' of the body.