Generation and Control are sustained by the principle of life that maintains both the bodily microcosm and the macrocosm. For life to manifest itself, it needs to grow in an orderly fashion: the Generation Cycle relates to growth and the Control Cycle to the limits that are needed to prevent growth beyond the natural possibilities of the energy or matter.
The human body, as a self-regulating entity, depends on the proper functioning of its 12 basic units that produce and store energy. The Sheng and Ke cycles maintain dynamic balance between them through the Five Elements.
Pathology
The alteration of this balance, whether from external or internal causes, will cause imbalances at the channel or organ level in the element related to that imbalance, and subsequently alter its coupled Yin or Yang (see Zang-Fu theory). Following the natural flow of energy, the remaining elements will be affected by excess or deficiency of the mother or child, the grandfather or grandchild, as the case may be. These imbalances are known as: Over-acting and Insulting Cycles
See more in Theory of the Five Elements