As the world goes dark, this master switch tells our pineal gland to increase levels of the hormone melatonin in the bloodstream, sort of like a chemical lullaby.
As you go to sleep and finally begin to drift off, melatonin is secreted by the pineal gland which begins the sleep cycle, which happens multiple times through the night.
These cells are found in glands, like the supratentorial pineal gland which is located just behind the third ventricle, or the infratentorial pituitary gland located near the front of the third ventricle.
And the master gland in your body is the pituitary, which produces many hormones that signal other glands — like the thyroid, parathyroid, adrenal, and pineal glands — to make their own hormones.
Every once in a while, sudden soreness triggered a twinge of discomfort and shame. Whoever said the soul and the body met in the pineal gland was a fool. It's the asshole, stupid.
As long as the mind is in the body, he believed, it is linked to the brain through a special brain organ which he called the pineal gland, where a constant interaction takes place between 'spirit' and 'matter.