The Vital Substances Qi can manifest in material and immaterial
ways. The material is associated with yin and the vital
substances and the immaterial with yang and the vital energies.
In humans, Qi can manifest both in physical form and in
physiological, psychological, and spiritual functions.
Individually, TCM refers to these energetic manifestations as
"the vital substances." (They include the vital energies of qi
and shen.) Each vital substance is associated with a particular
form and function in the body: - Jing (essence) is the most
concentrated and potential form of yin Qi in the body. It is
responsible for all growth and development; is associated with
the core structures of the body such as bones and visceral
organs; and is the energy of sex and reproduction. When the
jing-essence is deficient there can be congenital birth defects,
mental retardation, poor or weak constitution, delayed or slow
development, reproductive difficulties later in life, and a
shortened natural life span. TCM does not ever ta