The pineal gland is a small endocrine gland in thein of animals with backbones. The pineal The pineal gland, alsoed the pineal body, is part of the epithalamus, and lies between the laterally positioned During embryonic development, the parietal eye and the pineal organ of modern lizards and tuataras form .
The gland is reddish-gray and about the size of a grain of rice 5-8 mm in humans. The pineal gland, alsoed the pineal body, is part of the epithalamus, and lies between the laterally positioned thalamic bo.s and behind the habenular commissure. It is located in the quadrigeminal cistern near to the corpora quadrigemina..The pineal gland is a small, pinecone shaped gland of the endocrine system. A structure of thencephalon of thein , the pineal gland produces the hormone melatonin. Melatonin influencesual development and sleep-wake cycles..Pineal gland, alsoed conarium, epiphysis cerebri, pineal organ, or pineal body, endocrine gland found in verte.tes that is the source of melatonin, a hormone derived from tryptophan that plays a central role in the regulation of circadian rhythm the roughly 24-hour cycle of biological activitiesociated with natural periods of light and .Pineal Gland Essentials. Of the endocrine organs, the function of the pineal gland was the last discovered. Located deep in the center of thein, the pineal gland was once known as the "third eye." The pineal gland produces melatonin, which helps maintain circadian rhythm and regulate reproductive hormones..