Pineal gland

When the meditator is acquiring divine nature he shall hear the auspicious sound of OM.  This means his Kundalini is awakening.  This awakened KundalinI further will be hastened by Diensephalan. The Cerebrum & pineal gland are responsible for super conscious state. This super conscious state in Sanskrit is called Aadhyaatmika Kendra.

This pineal gland start drying up from the age of seventh year.  This leads to destruction of constructive attitude.  Limbic system in the brain is responsible for mental behaviour/subtle body. This mental state in Sanskrit is called Aadhidaiwika Kendra. Hypothelmus gland is responsible for  mental behaviour/subtle body.

Pituitary gland is behind the kootastha i.e., the place behind the eyes in the Aagna+chakra.

Hypothelmus gland is sandwiched between Aagna+chakra and Pituitary gland. 

This Aagna+chakra commands the physical body issuing instructions. This physical state in Sanskrit is called Aadi bhowtika Kendra.

Cerebellum is the coordinator of physical (Aadibhowtika) and super conscious (Aadhyaatmika) states.

The excitation of Pineal gland  is imperative for constructive ideas.  For this the third eye between two eye brows is required to be excited. For this kriyayoga and the chanting of Gayatri mantra is essential.  Using the Kriya yoga methods for opening of third eye shall lead to mental as well as physical happiness and hence healthiness.

Sound sleep—Pineal gland  

Melatonium is the chemical required for sound sleep.  If this chemical is active for 1½ hour it is enough for sound sleep. This Melatonium is organized by Pineal gland.  Because of the drying up of Pineal gland we will not get proper sleep and hence restlessness.