Advanced Qiogng theory talks about the Three Treasures: Jing, Qi, and Shen.
In addition to the organs and energy meridians our body also has three centers or collection points. These are called Dan Tien, which translates as field of elixir. Inside our body these fields are a place for cultivation. As the name suggests the cultivation process is similar to the way crops are cultivated in a field, with much care for making sure the environment is right for cultivation but not much meddling in the actual process of transformation. If you grow a plant you can make sure the soil is fertile and that the seedling gets air, water, and sun. But the plant grows on its own. You can not really help it along, you can only observe the changes and transformations that take place and adjust the conditions accordingly. For personal practice this would relate to a healthy lifestyle, good nutrition, and consistent practice. Over time the transformations in the body will take place naturally.
These three centers house what are called the Three Treasures: Jing, Qi, and Shen.
The Lower Dan Tien is located about 2-3 inches below the umbilicus and at the center of the body. This center is associated with Jing. Jing is the most coarse substance of the three and relates to the physical body. Jing is often translated into English as sperm and is the origin of life.
The Middle Dan Tien is located in the middle of the chest at about the level of the solar plexus. This center is associated with Qi or Energy. This center also relates to the mind.
The Upper Dan Tien is located in the head and is related to Shen. Shen is thought of as spirit or consciousness.
The Three Treasures (Jing, Qi, and Shen) are all related and can support and transform into each other. They are actually the same substance at different levels of refinement.
Shen is more refined/rarefied Qi.
Qi is more refined/rarefied Jing.
Once Jing becomes abundant it will transform into Qi. Once Qi becomes abundant it will transform into Shen.
The three treasures relate to practice in that they emphasize the physical training first. The body is the same as a container that must be filled from the bottom up. This means that in order to practice safely and avoid problems always start by having a strong physical foundation through training. Once this strong foundation is achieved the mind and spirit will be supported and healthy. With a strong foundation we can achieve higher goals in cultivation. If the foundation of physical work is neglected the energy in the body can become ungrounded.