Which part of the central nervous system acts as ‘master clock’ of our body?

Hypothalamus acts as a master clock in the human body. Suprachiasmatic nucleus, or SCN of hypothalamus receives input from the eyes (retina) and sends output to other hypothalamic nuclei, the reticular formation, and the pineal gland. Hypothalamus thus, is the master circadian clock that regulates 24-hour cycle. It controls emotional responses, regulates body temperature, and water balance, and arouses hunger drive.