The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland-produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The shape of the gland resembles a pine cone, which gives it its name.
Once called the ‘third eye,’ the pineal gland is a small gland located deep in the center of the brain. Named for its pinecone shape, this gland secretes melatonin, which plays a role in the body’s internal clock.