Referring to the organizational chart, lesya acts as a liaison between the spiritual self and the physical self of a living organism. It is the built-in mechanism within the organism through which the spiritual self can exercise its power and authority and control the functioning of the bodily organs. It deciphers the code of intangible psychic expressions (adhyavasaya) into a form, which is tangible and crude enough to control and function through such gross elements as flesh and bones. Of course, lesya derives much assistance from endocrine system in its function of intercommunication and manifestation in the physical body.
Lesya functions in both directions: centripetally, i.e. from periphery towards centre, as well as centrifugally i.e. from centre to periphery. Contaminating material is continuously attracted and collected from the external environment by threefold activities of the physical body viz., thought, speech and muscular action. This must be delivered to the sphere of kasaya at the centre in an acceptable subtle form. Similarly, whatever is radiated outwards from the subtle karma sarira at the centre is delivered to the gross physical body by lesya.