Q.Pineal gland is an endocrine gland, write its role.

The pineal gland secretes melatonin, which regulates the sleep-wake cycle (circadian rhythm) and influences the timing of reproductive maturity.

The pineal gland (epiphysis cerebri) is a small, pea-shaped endocrine gland located deep within the brain, attached to the roof of the diencephalon (epithalamus region).

Its principal secretion is melatonin, whose release is regulated by the light-dark cycle detected via the eyes: melatonin secretion increases in darkness and decreases in light. Through this mechanism the pineal gland:

• Regulates the body's circadian rhythm — the sleep-wake cycle and other daily biological rhythms.
• Helps the body adjust to seasonal changes in day length. …