There are 84 meridian points (similar to bundles of nerve endings) on the upper palate of the human mouth. One can feel that upper palate with the tongue and experience its different surfaces.

Two rows of meridian points are on the upper palate and on the gum behind the upper teeth. When we recite a mantra, our tongues touch these various pressure points in a sequence that stimulates the  hypothalamus  gland,  which  in  turn  makes  the  pineal  gland  radiate. 

People  talk  about  the  pineal  gland  secreting, but secreting hormones is only part of the story. The pineal gland is also sensitive to light. The great Chinese sage, Lao Tzu, called it “the gateway to heaven and earth.”

When the pineal gland radiates, it creates an impulse in the pituitary gland, the master gland of the body (the gland that is the gateway to intuition). Think of a garage opener, for instance, where you press a series of numbers and then the * (star) key, and the door opens! Well, mantra is a key that opens the doors of inner awareness.

When the pituitary gland gives impulses, the entire glandular system secretes and a human being experiences bliss. This is the science.

~MSS Guruka Singh Khalsa, “The Science of Sound,” Heroes, Saints and Yogis (2012) by Shakti Parwha Kaur Khalsa and Guruka Singh Khalsa.