ALPHABETICAL BRAIN VOCABULARY Flash Card #40 - Details WHAT IS YOUR "PINEAL GLAND" AND WHY IS IT SO IMPORTANT? Your PINEAL GLAND system is two small clumps of NEURONS in your LIMBIC SYSTEM that point to the BACK of your head and regulate your daily CIRCADIAN CYCLE ("sleep-wake" cycle). Together, they produce the hormone MELATONIN. Return to #40: PINEAL GLAND or BRAIN FACTS MATRIX