The hypothalamus consists of a tiny cluster of nerve cells located at the center of the base of the brain. This organ serves as a link between the autonomic nervous system and the endocrine system. The hypothalamus is responsible for many body functions. Its function is to integrate and ensure appropriate response to stimuli. It regulates hunger, thirst, sleep, and wakefulness. It also plays an important role in the regulation of most of the involuntary mechanisms of the body, including body temperature, sexual drive, and the female menstrual cycle. The hypothalamus also regulates the work of the pituitary gland.