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Concept of essence

Essence refers to the basic material to form and sustain life activities of the human body, consisting of innate essence from parents and acquired food essence.

Generation of essence

The generation of essence is of two sources, namely the innate source and acquired essence. The innate essence is the innate reproductive essence from parents, the origin of life, and the material basis of growth and reproduction of the body mainly stored in kidneys. The acquired essence refers to food essence generated by the spleen and stomach. Food essence is generated after birth, so it is known as acquired essence.

Innate essence and the acquired essence have different sources, but they are interdependent and interpromoting. The innate essence is the premises for the generation of acquired essence while acquired essence can supplement and enrich the innate essence. The innate essence and acquired essence can combine to form the essence of the whole body to be stored in viscera. Deficiency of innate essence and acquired essence can both affect the generation of essence of the body resulting into the pathological changes of essence deficiency.

Functions of essence

1. Reproduction

The innate essence from parents is the material basis for the pregnancy and the origin of life. After birth, innate essence stored in kidneys becomes prosperous under the supplement and nourishment of acquired essence, and can generate sex-stimulating essence and promote maturity of the reproductive function, manifesting as man's ejaculation and woman's menstruation. Therefore essence is the material basis for the reproduction. The abundance of kidney essence ensures the prosperity of reproduction, and the deficiency of kidney essence can affect the reproductive function. In clinic, infertility and other disorders of reproductive function are usually treated by tonifying kidney and enriching essence.

2. Growth and development

Essence of the human body can promote the growth and development of the human body. Essence is the major material basis in different stages of the growth and development of the human body. The stage of kidney essence affects the whole life process.

During embryonic period, the innate essence is not only the material basis for the formation of constituents and viscera, but can promote the growth and development of fetus. After birth, with the incessantly enrichment of innate and aequired essence, the human body develops to maturation, and the human body becomes aged with the depletion of innate and acquired essence. The deficiency of essence of the human body can affect the growth and development manifesting as retarded growth and development as well as premature senility.

3. Generating marrow and blood

Essence stored in kidney can generate marrow, including bone marrow, spinal cord and brain. Therefore, the abundance of the kidney essence ensures prosperous generation of marrow that can supplement and tonify bone and brain. Otherwise, the deficiency of kidney essence can cause the deficient generation of marrow to affect the function of the bone and brain.

As for the generation of blood, the food essence can transform into blood through heart qi and lung qi's transformation action, and on the other hand, kidney essence generates bone marrow to produce blood, so essence also is the material basis for the blood generation. Deficiency of food essence and kidney essence both can affect the generation of blood leading to blood deficiency.

4. Nourishing the body

Essence can nourish the viscera and constituents of the whole body. Through the digestion of the spleen and stomach, food can transform into food essence distributed to the whole body to nourish the viscera and constituents so as to maintain the life activities. Essence stored in kidney also is distributed to the whole body to nourish viscera and constituents.