Together with the Zang-fu organs and the channels and collaterals, constitute the theoretical basis of human physiology in traditional Chinese medicine. Qi connotes both substance and function. The essence of food derived by digestion and absorption of the spleen and stomach is transported to the heart and lung and transformed into red blood by the two organs. The kidney stores essence. The essence of the kidney produces bone marrow, which in turn produces blood.
Blood is formed from essence, including the essence of food and essence of the kidney.
The Qi of the kidney promotes transportation and transformation by the spleen and stomach and strengthens the blood formation. Blood is constituted of nutrient Qi, body fluid and essence of the kidney, the material base for the functioning of blood is to circulate in the vessels nourishing the body and promote the functional activities of various tissues and organs. Blood and Qi are closely related. Body Fluid Food and drink, especially the latter, after absorption become body fluid, which exists in the blood and the interstices of the tissues.