HAIR-GROWTH AND COAT CHANGE - AN ADDITIONAL FUNCTIONAL STRAIN ON THE SKIN - AT THE EXAMPLE OF MEDULLATED PRIMARY FOLLICLES

The hair cycle is a temporary challenge of such a high degree that the skin's other functional capacity, i. e. to serve as a sheltering barrier, is partly restricted. In order to be able to explain this phenomenon and its consequences, the development and growth of the anagen primary hair follicle as well as its subsequent involution to the state of a telogen hair follicle are described. The demonstration of important endogenous and exogenous factors that substantially influence and control the whole process is supposed to emphasize the complexity of the hair cycle. In this connexion one must not forget that domestication and breeding play a significant role for the fact that there is a shift from periodic to continuous hair shedding.