What is pineal gland primarily responsible for? In your endocrine system, what is the pineal gland primarily responsible for controlling?
The pineal gland is responsible for controlling the production of the hormone melatonin, which helps to regulate sleep. Melatonin production increases when there is less light present, making humans sleepy. The pineal gland includes light sensitive cells, which are activated through the retina of the eye. These cells can sense how much light is present, and signal the gland to make more or less melatonin.