In hermetic alchemical belief and practice, the planets corresponded to organs in the body. There were seven known planets with Saturn being the farthest out. Therefore, Saturn was seen as the entry from the void.
Sun: Crown Chakra – pineal gland – also Sun plus Venus relationship –pineal gland creates melatonin (but only in the dark). Melatonin corrects genetic mutations and controls circadian rhythms.
Moon: Brow, brain, eyes – pituitary gland – receptive (female) – perceive world and perceive thoughts.
Venus: heart center (water and fire) – as center of the body, this area is meant as the place humanity works from (love) – kidneys and thymus – understanding.
Mars: solar plexus – gall bladder and digestion – will power.
Jupiter: sex – soul, oil, liver – creation (emotions).
Saturn: root (entry from the void) – spleen – foundation.