There are also more specific ways that the word "qi" is used. Practitioners of acupuncture and Chinese herbal medicine, for instance, have identified various kinds of qi that function within the human body. In this context, qi is one part of the Qi/Blood/Body-Fluids trinity of substances fundamental to the body’s internal functioning.
Of the three, Qi is attributed to yang, because it is mobile and has the job of moving and warming things. Blood and Body Fluids, on the other hand, are attributed to yin, because they are less mobile, and have the job of nourishing and moistening things.
The Qi Of Specific Organ Systems:
Each of the Zang-Fu Organ Systems has a particular Qi – which in this context simply refers to its primary function.
Spleen Qi, for instance, is responsible for transformation and transportation (of food and fluids, primarily). Lung Qi governs breathing and voice. Liver Qi is responsible for the free flow of emotional energy. Heart Qi governs the flow of blood through the vessels. Kidney Qi is associated with the primordial energy that we inherited from our parents. Likewise, each of the other Zang-Fu has a specific "qi" that points to its unique function within the body.