8-12.Kind of wrinkle：Wrinbkle　and　collagen
	Collagen that is overcrowded and forms protein structure ●The skin thins growing old. It tends to thin with the age after a peak of one's twenties afterwards when the thickness of dermis is measured. It is thought that the amount of collagen decreases along with it, too. Collagen fiber is overcrowded in detail in papillary layer of dermis, and fatter fiber is intertwined loosely in reticular layer. The direction of fiber is a complex, three-dimensional reticulation structure.
							This protein structure becomes a source that invents elasticity and the retractility of the skin. When pressure is excluded, it restores it to the origin though a reticulation structure is transformed when pressured from the outside. When restoring it, working of Erastin of elasticity fiber is greatly related, too.
	However, the reticulation structure of collagen feiber becomes sparse when growing old, and fiber becomes thin one per one, too. Moreover, it becomes a straight line, and there is often a state that intertwining fiber starts being almost lost, and getting loose, too. A decrease of such collagen fiber leads to the loss of the elasticity of the skin, and causes the wrinkle.
	Change in collagen「Bridge imposing」 ●There is a change in a molecular uniting fiber in addition to a decrease in collagen fiber with aging, too. As for collagen fiber, the molecule is connected with the molecule by constructing a bridge (bridge imposing) each other. It is called "bridge imposing" because it crosses between fiber like having built the bridge, and it unites. It tends to pile up the age and to increase though this bridge imposing leaves space constancy for a young, healthy skin and exists. Collagen fiber of bridge imposing of a constant number is very important in the meaning that keeps strength at regular intervals. However, working of collagen fiber is obstructed, and the skin organization is caused to stiffen for the bridge of which number increases by aging or disregarding. An increase of bridge imposing is a cause of the wrinkle and slack.
	As for healthy collagen fiber, the determination edge is connected by the determination edge and the bridged structure (bridge imposing) of other collagen fiber. The skin keeps elasticity by this. It becomes hard collagen fiber when it is possible to injure, and flexibility is lost more than the necessity between fiber growing old the bridge.