Question Detail

The major component of the biological clock (circadian rhythm) in higher vertebrates is the suprachiasmatic nucleus (SCN), located in the hypothalamus. The SCN receives direct input from the eyes and coordinates daily rhythms of sleep-wake, hormone secretion, and other physiological processes. The pituitary gland is involved in endocrine regulation but is not the central pacemaker; the cerebral cortex and medulla oblongata are not primarily involved in circadian timing.